HONG KONG • Rights group Amnesty International has urged the Hong Kong authorities to urgently investigate a bloody attack on the leader of one of the biggest pro-democracy groups in the Chinese-ruled city, ahead of a march planned for the weekend.

It was the second such attack on Mr Jimmy Sham, head of the Civil Human Rights Front, since protests escalated in the Asian financial hub in mid-June and one which, photographs on social media showed, left him in a pool of blood on the street.

"The authorities must promptly conduct an investigation into this horrifying attack... send a clear message that targeting activists will have consequences," said Mr Joshua Rosenzweig, head of Amnesty's East Asia regional office.

"Anything less would send a chilling signal that such attacks are tolerated by the authorities," he said in a statement on Wednesday.

As many as five masked men wearing black and believed to be of non-Chinese origin had attacked Mr Sham with hammers and knives for more than 10 seconds in the Mong Kok district on the Kowloon peninsula, police said late on Wednesday.

The police condemned what they called a planned attack, and promised to investigate. Mr Sham was in a stable condition, said a government spokesman.

His group, which organised the million-strong marches in June, has planned a march for Sunday, but the authorities have not yet confirmed that it will be permitted.

Mr Sham issued a plea from his hospital bed yesterday for police to allow the march to go ahead in the Tsim Sha Tsui area as planned.

"Many of the citizens expressed that they really hope there will be a safe march on Sunday," the Civil Human Rights Front said in a statement yesterday. "Jimmy therefore urges the police to issue Letter of No Objection so that Hong Kongers can express their views."

Speaking at the city's legislature yesterday, nearly a dozen pro-democracy lawmakers condemned the attack on Mr Sham, and said they would continue to protest.

REUTERS, BLOOMBERG