Some protesters, unhappy with what they called "failed" strategies of the Federation of Students, tried to mobilise chat room members after police destroyed barricades on Queensway on Tuesday. They vowed to block Lung Wo Road, the main route to the chief executive's office in Admiralty.

Before 10pm on Tuesday, dozens of youths blocked the west-bound traffic of Lung Wo Road with barricades.

Some police officers arrived. Tensions flared after the officers tried to subdue and take away a young protester. After about an hour, the police, outnumbered by the crowd, retreated.

Online posts continued. At about midnight, a thread on Hong Kong Golden suggested that water tanks be deployed to flood the tunnel. Again, it's not clear who the author was.

At 1.10am yesterday, another thread thanked members of another online chat room, Hong Kong Discuss Forum, for helping.

The crowds on Lung Wo continued to swell. Many worked to erect barriers inside the Lung Wo tunnel, piling plastic street barriers and concrete drain covers to block the tunnel.

A teenage protester said the new road blocks were created after police destroyed the elaborate barricades on Queensway - flattened by officers in 45 minutes on Tuesday. "Some protesters came to occupy Lung Wo Road because they were unhappy that the police had cleared the road barriers in Queensway. They mobilised people via the [internet] and vowed to let the police pay the price."

At about 2.45am hundreds of police officers marched west and east on Lung Wo to Tamar Park, trapping hundreds of protesters. Using pepper spray and riot shields, the officers collared some and dragged them away, leaving people to try to flee the enclosed area, some by climbing over the barricades on Tim Wa Avenue.

Members of the media and people taking photos were not spared. A reporter was hit on her leg with a chair thrown aside by approaching officers.

Lawmaker Leung Kwok-hung, known as "Long Hair", of the League of Social Democrats, appeared to panic. "Retreat! Retreat! Retreat!" he shouted. His pleas were drowned out by the protesters' screams.

Forty-five protesters - 37 men and eight women, aged 17 to 54 - were arrested.

A hairdresser, aged 27, said the overnight clearance was the most chaotic scene he had experienced in the eight days he had camped outside the Chief Executive's Office.

"Some police officers dragged protesters who were already pushed to the ground … and swore at protesters," he said. They pulled down tents when people were still in them." The police, he said, "were fuelled by hatred".

Manson Yip, 19, condemned the police. "They not only pushed the crowd back, they punched the protesters," Yip said.

Hours later, broadcaster TVB aired footage appearing to show police officers in vests escorting a protester with bound hands to a dark corner, away from the crowds. There, several police kick the fallen man, while one officer stands guard. The man was identified by colleagues and in photographs as Civic Party member Ken Tsang Kin-chiu.

Police said they had launched an investigation into the incident.