Activists blockaded two terminals in the city on Tuesday in the latest escalation of a 10-week political crisis that has gripped the international finance hub and forced the closure of the airport.

A small group of protesters also surrounded, tied up and beat a man wearing a yellow journalist vest -- whom the editor of China's state-controlled Global Times identified as one of the paper's reporters -- and another man Beijing said was a Shenzhen resident visiting Hong Kong.

"We express the strongest condemnation of these terrorist-like actions," said Xu Luying, spokeswoman at the Hong Kong and Macao Affairs of the State Council, who called the two men "mainland China compatriots."

The man Xu identified as a Shenzhen resident was held for about two hours before eventually being taken away in an ambulance.

The actions of the protesters "seriously damage the international image of Hong Kong, and seriously hurt the feelings of a vast number of mainland China compatriots", said Xu, saying the "extremely abominable violent crime must be severely punished according to the law".

"We resolutely support the Hong Kong police force and judiciary... to decisively enforce... and bring the criminals to justice as soon as possible."

In Hong Kong, weeks of rallies, demonstrations and occupations have seen millions of people take to the streets in the biggest challenge to China's rule of the semi-autonomous city since its 1997 handover from Britain.

Initially sparked by opposition to a planned law that would have allowed extraditions to mainland China, the protests have quickly evolved into a much broader campaign for democratic freedoms, and to stop the growing influence of China's authoritarian rulers in the semi-autonomous city.