Hong kong deployed thousands of riot police on thursday to quell one of the territorys first attempts at large co-ordinated protests since china imposed a tough national security law on the city in june.

Police also targeted journalists covering the demonstrations, which were held to mark chinas national day, in the latest move to crack down on hong kongs freewheeling press.

In one of hong kongs busiest retail districts, small groups of protesters taunted officers by weaving through crowds of shoppers and shouting slogans before disappearing again.

The protesters, some of whom wore yellow masks the chosen colour of hong kongs protest movement were cheered on by a group of older women on a double-decker bus who blew on horns and clapped.

Of course [we are afraid] but despite the fear we should not stop what we are fighting for, a 27-year-old teacher said. we still want democracy and we still need freedom and we still want our hong kong.

Beijing introduced the security law after anti-government protests swept through hong kong last year. the legislation targets collusion, subversion and foreign interference with punishments of up to life in prison.

Protesters on thursday also called for the release of 12 hong kong activists being held on the chinese mainland after they were caught fleeing to taiwan by boat.

Local media said the government deployed 6,000 officers to secure the city against national day protests. police screened whole streets of shoppers, including young children, for evidence they were protesters and placed several mostly young people, their hands secured with cable ties, on to buses.

Police said 69 people were arrested for illegal assembly including two elected politicians from hong kongs local district councils.

Officers also began implementing a tougher system for dealing with reporters, crowding local and international media into a tightly packed makeshift pen.

Only journalists from media approved by the police were permitted to leave while those remaining underwent further checks to see if they were protesters.

In september, the citys police unilaterally stopped recognising press cards issued by the hong kong journalists association, the private sector representative body for the industry.

Thursdays protests were the first in which the police also began doing their own live broadcasts of the events on facebook, even using presenters to narrate events.

The hong kong journalists association complained that the restrictions prevented reporters from doing their jobs.

Hong kong is an international city and we have freedom of the press protected under the basic law, said the associations bruce lui, a journalism lecturer at the hong kong baptist university, referring to the citys mini-constitution.

Freelance journalists and online media captured some of the key images of last years protests, which started when the government attempted to introduce a law to allow criminal suspects to be extradited to mainland china.

The protests evolved into a broad movement to stop beijing limiting freedoms promised to hong kong on its 1997 handover to china from the uk.