Hong Kong protest organizer attacked with hammers and knives

Hong Kong (CNN)The leader of one of Hong Kong's most prominent pro-democracy groups was hospitalized Wednesday evening after being attacked by a group of men wielding hammers and knives.

Jimmy Sham, convenor of the Civil Human Rights Front (CHRF), which has organized some of the largest protests during Hong Kong's four-month-long civil unrest, suffered wounds to the back of his skull and forehead, police said.

Photos from the incident showed Sham lying on the street covered in blood.

Warning: The images below have graphic content.

Hong Kong Police said Sham was attacked by four males "of non-Chinese descent" who were wearing masks and dressed in black, Chief Inspector of Mong Kok District, Ng Tak-nam, said in a press conference late Wednesday.

Blood is seen beyond a police cordon, where Jimmy Sham was assaulted on October 16, 2019.

Some of the assailants set upon Sham with hammers while others used knives in the attack, which happened at 7:40 p.m. local time (7:40 a.m. ET) in Kowloon's Mong Kok district, Ng said. The attackers fled the scene in a private car and are still at large.

The CHRF said in a statement that Sham was conscious when taken to hospital where he received "emergency treatment." He is now in a stable condition.

It is the second time the activist has been attacked in less than two months. On August 29, Sham was attacked by masked men carrying baseball bats and knives in Kowloon district. On the same day, police banned a rally and march planned by the CHRF that weekend.

The group condemned the assault and called on police to conduct a thorough investigation to find the perpetrators. They are waiting for police approval for another protest on Sunday.

"It is not hard to link this incident to a spreading political terror in order to threaten and inhibit the legitimate exercise of natural and legal rights," the CHRF said in a statement.

Police condemned the "cruel and pre-planned violent incident" and said they had "assigned staff to safeguard Sham in hospital."

Civil Human Rights Front convenor Jimmy Sham sustained head injuries when he was attacked by a group of masked men. He is now in a stable condition.

Amnesty International has urged Hong Kong authorities to launch a "prompt and thorough investigation into a brutal attack."

"Jimmy Sham was left bleeding on the street and has been hospitalized with head injuries. Even in the context of increasing attacks on activists, this incident is shocking in its brutality," Joshua Rosenzweig, Head of Amnesty International's East Asia Regional Office, said in a statement.

The incident comes a day after Hong Kong Chief Executive Carrie Lam was forced to abandon her annual police address after pro-democracy lawmakers repeatedly disrupted her speech and heckled her with calls to honor the demands of months-long anti-government protests.

Her address had been seen as a key opportunity for Lam to begin to remedy some of the perceived factors behind the unrest, such as widespread inequality and limited access to public housing.

Pro-democracy lawmakers protest as Hong Kong Chief Executive Carrie Lam delivers a speech at the chamber of the Legislative Council in Hong Kong Wednesday, October 16.

Hong Kong Chief Executive Carrie Lam arrives to deliver her policies at the chamber of the Legislative Council in Hong Kong, on Wednesday.

A protestor shoots a basketball at a poster of Hong Kong Chief Executive Carrie Lam at the Southorn Playground in Hong Kong during a rally in support of NBA basketball Rockets general manager Daryl Morey and against comments made by Lakers superstar LeBron James on Tuesday, October 15.

Protesters set fire to a Bank of China branch in Hong Kong on Sunday, October 13. It was the 19th consecutive weekend of anti-government protests in Hong Kong.

Protesters use the lights on their phones during a rally in central Hong Kong's business district.

A protester attempts to break a tourist bus window on October 13.

Protesters wearing masks in defiance of a recently imposed ban gather at a shopping mall on October 13.

Anti-government protesters set up "The Lady Liberty of Hong Kong" statue, which symbolizes the city's recent democratic movement. The figure stands a little over 13 feet tall and was carried in pieces to the top of Lion Rock, one of Hong Kong's iconic peaks.

Protesters vandalize a shopping mall restaurant on October 13.

Supporters surround a police bus carrying political activist Edward Leung as it leaves the High Court in Hong Kong on Wednesday, October 9. Several hundred masked protesters gathered at Hong Kong's High Court for the appeal hearing of Leung, who was sentenced to six years in prison for his part in a violent clash with police.

Police shine lights at protesters outside the Ma On Shan police station on October 9.

Protesters smash up a Bank of China branch on Monday, October 7.

A woman is treated after police fired tear gas to disperse protesters in the Mong Kok district of Hong Kong on October 7.

Police clear a street as protesters and pedestrians gathered near the Mong Kok police station on October 7.

Pro-democracy protesters gather in a shopping mall on October 7.

A masked protester stops for a portrait in Hong Kong on Sunday, October 6.

Protesters vandalize the Cheung Sha Wan local government offices on October 6.

Rescue personnel check the bottom of a taxi after the driver allegedly drove onto the pavement, hitting protesters in Hong Kong on October 6.

A China Construction Bank is seen vandalized in the Causeway Bay area of Hong Kong on October 6.

Pro-democracy protesters set fires in the street in the Causeway Bay area.

People protest the ban against masks on Saturday, October 5.

Police detain a protester on October 5.

An anti-government protester stands near a fire on Friday, October 4.

Protesters move a statue depicting a protester armed with gas mask, helmet and umbrella on the streets of Hong Kong on October 4.

Protesters set a fire at a China Construction Bank.

Police deploy tear gas outside a restaurant during a protest in the Causeway Bay district.

Protesters spray paint slogans at the entrance to a tunnel on October 4.

A fire is seen in front of a store vandalized by protesters.

A store after being vandalized by protesters.

Pro-democracy demonstrators hold up their hands to symbolize their five demands during a rally on October 4.

Protesters throw petrol bombs at the gate to the Tsuen Wan police station on Wednesday, October 2.

Schoolmates of a student who was shot in the chest by police place their hands on their chests during a protest on October 2.

A young protester was shot Tuesday, October 1, as violent protests erupted across Hong Kong on the 70th anniversary of the People's Republic of China. The incident marked a major escalation in violence that could galvanize the protest movement in Hong Kong.

Police detain an anti-government protester on October 1. Thousands of black-clad protesters marched in central Hong Kong as part of multiple pro-democracy rallies.

Protesters stand surrounded by smoke from tear gas shells on October 1.

Marching anti-government protesters are seen through a window with peeled-off posters on October 1.

Police tackle and arrest pro-democracy protesters during clashes on October 1.

A protester is seen carrying rocks on a street on October 1. While events in Beijing were being held to mark the 70th anniversary of the founding of the People's Republic of China, demonstrators rallied throughout Hong Kong.

Protesters react after police fired tear gas near the central government offices in Hong Kong's Admiralty area on October 1.

Pro-democracy protesters form a "Pepe the Frog" themed human chain on Monday, September 30.

A man is detained by Hong Kong police during a protest in the Causeway Bay shopping district on Sunday, September 29.

Riot police try to disperse protesters on September 29.

Bus passengers look at a burning barricade lit by pro-democracy protesters in front of the Mong Kok police station on Sunday, September 22.

Pro-democracy protesters sing songs and chant slogans during a rally inside a shopping mall on September 22.

An anti-government protester throws a Molotov cocktail during a demonstration near the Central Government Complex on Sunday, September 15.

A pro-China supporter, center, is escorted by police after confronting journalists in Hong Kong on September 15.

Pro-government and anti-government supporters chant against one another at a shopping mall in Hong Kong on Friday, September 13. The sign translates to "Stop violence and curb chaos; safeguard Hong Kong."

Demonstrators hold up their cell phone lights as they form a human chain at the Peak, a tourist spot in Hong Kong, on September 13.

Police escort an injured man after he attacked protesters outside Prince Edward station in Hong Kong on Friday, September 6.

Protesters burn paper money to pay their respects to injured protesters.

Protesters prepare to clash with police outside the Mong Kok police station on September 6.

A protester is detained by police at the Po Lam Mass Transit Railway station on Thursday, September 5.

A man watches televisions at a store in Hong Kong as Chief Executive Carrie Lam announces the withdrawal of the extradition bill on Wednesday, September 4.

A woman gets emotional on September 4 while paying her respects to protesters who were injured a few days earlier.

Demonstrators travel through a railway station during a rally on Tuesday, September 3.

Students wearing gas masks and helmets hold a banner that reads "five major demands are indispensable" at St. Francis' Canossian College in Hong Kong.

Protesters gather in the bus terminal at Hong Kong International Airport on Sunday, September 1. Hundreds of pro-democracy activists attempted to block transport routes to the city's airport.

A passenger walks to the airport on September 1 as pro-democracy protesters blocked a road outside the airport.

A protester uses a slingshot outside the Central Government Complex during clashes with police on Saturday, August 31. Thousands of pro-democracy protesters held an anti-government rally one day after several leading activists and lawmakers were arrested in a sweeping crackdown.

Protesters light a Molotov cocktail on August 31.

Police officers move forward during clashes with protesters on August 31.

Protesters take cover as policemen fire blue-colored water on them. Blue dye can be used to stain and identify masked protesters.

A surveillance camera is covered with white paint during protests.

An overhead view shows protesters reacting after police fired tear gas on August 31.

Pro-democracy activists Agnes Chow and Joshua Wong speak to the media after they were released on bail at the Eastern Magistrates Courts on Friday, August 30. They were arrested earlier the same day in a dragnet across Hong Kong.

Protesters clash with police after a rally in Hong Kong's Tsuen Wan district on Sunday, August 25. It was one of the most violent nights seen in Hong Kong since mass protests began in June.

A police officer aims a gun in front of a protester on August 25.

Some protesters shine laser pointers at police lines on August 25.

Protesters and police clash on Saturday, August 24.

Protesters pick up bricks to be used as projectiles on August 24.

Police retreat after clashing with protesters on August 24.

People link hands as they gather at the Tsim Sha Tsui waterfront on Friday, August 23. Protesters formed a human chain across Hong Kong in a show of solidarity.

Cell phones shine from the top of Lion Rock on August 23.

Protesters march under umbrellas on Sunday, August 18.

Tens of thousands of protesters showed up in the streets on August 18.

A protester participates in a march on Saturday, August 17. His eye is covered with red gauze, referencing a woman who was allegedly shot in the eye with a beanbag round during clashes between protesters and police.

Protesters react after police fired tear gas to disperse a demonstration at the Sham Shui Po police station in Hong Kong on Wednesday, August 14.

Protesters point lasers at the Sham Shui Po police station on August 14.

A police officer falls over an airport luggage trolley during a scuffle with pro-democracy protesters on Tuesday, August 13. For two days, protesters flooded the airport. Check-ins were suspended and dozens of outgoing flights were canceled.

Police use pepper spray to disperse protesters at the airport on August 13.

Police and protesters clash at the airport on August 13. The violence came after Hong Kong's Airport Authority announced that all check-in services would be suspended for another night because of terminal operations being "seriously disrupted."

A traveler passes her luggage to security guards as she tries to enter the departures gate.

A display board shows canceled flights on August 13.

Anti-government protesters stand at a barricade made of luggage trolleys during a demonstration at the airport on August 13.

Medics look after a woman who received a facial injury during clashes on Sunday, August 11.

A pro-democracy protester is held by police outside the Tsim Sha Tsui police station on August 11.

Police fire tear gas at protesters during a demonstration in the Wong Tai Sin District on Monday, August 5.

A train passenger gestures toward a protester, right, who was preventing the doors of a train from closing on August 5. The protester was trying to disrupt Hong Kong's morning rush-hour commute.

A man lies down on an underground train during a protest on August 5.

A man comforts his pregnant wife near a train platform after protesters blocked the train doors on August 5.

A protester stands in tear gas during a confrontation with police in the early hours of Sunday, August 4.

A Chinese flag floats in water after it was thrown by protesters during a demonstration on Saturday, August 3.

A protester sprays paint on a wall on August 3.

Members of Hong Kong's medical sector attend a protest in Edinburgh Place on Friday, August 2.

The emblem on the China Liaison Office is protected by plexiglass during a demonstration on Sunday, July 28.

A protester flees from baton-wielding police in the Yuen Long district of Hong Kong on Saturday, July 27.

A protester looks through umbrellas during the clashes with police on July 27.

Travelers watch as protesters rally at Hong Kong's international airport on Friday, July 26.

Protesters clash with police on Sunday, July 21.

Masked men in white T-shirts are seen after attacking anti-extradition bill demonstrators at a train station in Yuen Long.

Medical workers help a protester affected by tear gas on July 21.

The office of pro-Beijing lawmaker Junius Ho was trashed by protesters in Hong Kong's Tsuen Wan district.

Police officers use pepper spray to disperse protesters after a rally in the Sheung Shui district on Saturday, July 13.

A demonstrator sprays paint inside a chamber at Hong Kong's Legislative Council building, where protesters forced their way in on Monday, July 1.

The meeting hall of the Legislative Council is taken over by demonstrators on July 1.

A protester smashes a window of the Legislative Council building.

Columns of sunlight are cast on a crowd during the march on July 1.

Helicopters carrying the flags of China and Hong Kong fly over demonstrators on July 1.

Pro-democracy lawmaker Roy Kwong rallies demonstrators with a megaphone on July 1.

A police officer uses pepper spray during a clash with protesters on July 1.

A protester wearing a T-shirt with the word "revolution" walks past an inscription on a road that reads "Long Live HK."

Police detain protesters near the government headquarters in Hong Kong on July 1.

An overhead view shows thousands of protesters marching through a Hong Kong street on Sunday, June 16.

Protesters run after police fired tear gas on Wednesday, June 12.

Protesters face off with police during the rally on June 12.

By the morning of June 12, tens of thousands of mainly young people had arrived in the area, blocking streets and bringing central Hong Kong to a standstill.

A demonstrator holds a sign during the June 12 rally.

Police officers charge toward protesters during clashes on Monday, June 10. It was a continuation of protests that started the day before.

Protesters hold pictures of Hong Kong Chief Executive Carrie Lam on Sunday, June 9.

Protesters on June 9 waved placards and wore white -- the designated color of the rally. "Hong Kong, never give up!" some chanted.

Students wear chains during a demonstration on Saturday, June 8.

Civic Party lawmaker Tanya Chan accused Lam of having "blood on her hands" and said she had no right to address lawmakers due to the chaos unleashed by Lam's now-shelved extradition bill with China.

Protests which began over the bill have now lasted more than four months, with the movement's demands expanding to include other issues such as an independent investigation into police brutality and democratic reforms.

While protests began peacefully, with hundreds of thousands turning out for anti-extradition bill marches, they have grown increasingly violent. Protesters regularly throw petrol bombs and bricks, and have begun vandalizing subway stations and China-linked businesses, as police respond with tear gas and water cannon.

On Wednesday, police arrested two people on suspicion of making explosives, days after a bomb was set off near a police car following another night of violent protests.

CNN's Stella Ko and James Griffiths contributed.

By Helen Regan, CNN >>