HONG KONG -- A Hong Kong court on Thursday banned a high-profile student leader from going near a recently cleared protest site, constraining the pro-democracy movement as it enters a third month.

Joshua Wong, an 18-year-old who has become the most prominent of Hong Kong's protest leaders, was also given bail and his case adjourned until January 14.

Wong was among a group of protesters arrested during an operation by authorities the day before to finish clearing the protest site in the volatile Mong Kok neighbourhood.

Police and court officers moved swiftly to shut down the camp on a busy road, arresting more than 150 people during the operation and in ensuing scuffles on surrounding streets. The site had been one of three across the city occupied by protesters demanding greater democratic reforms than those allowed by Beijing.

Wong, head of the Scholarism group, was arrested along with another popular leader, Lester Shum, second-in-command of the Hong Kong Federation of Students, and pro-democracy lawmaker Leung Kwok-hung. They also faced the same conditions.

The arrests come as the democracy protest movement moves into a critical phase. The student groups have played key roles in organizing the protests but are now fighting to maintain momentum as the protests drag on with little to show for their efforts while the government patiently waits it out and police step up aggressive tactics.

Yvonne Leung, another Federation of Students leader, told a local radio station that the group would soon announce plans to escalate their tactics if police did not back off, which could include targeting "government-related" buildings or departments. She was not more specific.

Wong rose to prominence leading a campaign that in 2012 forced the government to back down from a plan to introduce Chinese patriotic education in schools that many saw as brainwashing. He told reporters after leaving court that he thought he was targeted by police while observing the barricade clearance.

"The clearance operation leader pointed to me and said 'arrest him'," Wong said. "Ten officers in blue shirts charged in front of me, pressed me to the ground and stopped me from moving. I received a bruise on my neck and they also injured me six or seven times in my private parts."

Video of the incident shows Wong standing among a crowd when an officer runs over to him and pulls him to the ground. He's swallowed up by a crowd of other officers and taken away.

Prosecutors applied successfully for a restraining order preventing Wong from entering a large swath of Mong Kok except when travelling through the area by subway. The judge made an exception to allow him to leave the subway station to walk to a minibus stop so he can go to his university.

Wong is charged with obstructing public officers. His lawyer argued that authorities wanted to keep him away from Mong Kok, a hotbed for more radically outspoken democracy activists that has become a flash point for confrontation with police.

"I suggest the real reason for the charges against my client is that he is a leader of the student protest movement," Michael Vidler told the judge.