China expressed strong indignation on Friday, condemning the attack on Hong Kong's justice secretary, saying such aggressive behavior must be stopped and severely punished.

Secretary for Justice Teresa Cheung was attacked by violent radicals when attending an event in London on Thursday, which caused her serious bodily harm.

Foreign Ministry spokesman Geng Shuang told a daily news briefing that the Chinese embassy in London has already sent staff to deal with the situation and asked the British side to provide safety protection for Cheung. Chinese ambassador to the United Kingdom Liu Xiaoming will also visit her.

It has been proved that the anti-China rioters are totally violent offenders, and their behaviors have breached the law and civility, Geng said.

Further tolerance of their behaviour will not only undermine the prosperity and stability of Hong Kong, but will also bring serious disruption and damage to the international community, including the UK.

The spokesman pointed out that the hideous attack is directly linked with the behaviors of some British politicians who distort facts, confuse right with wrong and encourage violent crimes as well as bolster anti-China rioters.

"If the UK does not change its wrong doings and continue adding fuel to the flames, such move will backfire and their own interests will be harmed," he claimed.

China demands the UK to investigate the case, arrest the culprits and bring them to justice, and earnestly protect the safety and dignity of all Chinese nationals in the country, Geng said.

He urged the UK to remain silent in words and deeds regarding the Hong Kong related issue, stop sending wrong signals and meddling in Hong Kong's affairs.