Scuffles broke out as about two dozen men wearing surgical masks tried to tear down the metal barricades that protesters have set up to block off main roads near the heart of Hong Kong’s financial district.
Some were seen using Stanley knives to snap cables connecting the barricades.
Several hundred people rushed to the barricades, chanting “Open the road”. They also shouted “Occupy Central is illegal”, referring to one of the names of the pro-democracy movement that has swept Hong Kong.
Taxi drivers joined in, some driving their cabs up to the barricades and leaning on their horns to express their anger about traffic disruption.
A line of police officers held the crowd back, keeping them separated from the protesters, who accused the attackers of being members of triads, or organised crime gangs.
The tension later eased as the most of the crowd dispersed. Police took away some masked men inside the protest zone who tried to pick fights with the protesters, and later said that they arrested three men, aged 18 to 47, on suspicion of assault and carrying weapons.
“Before the police came, young men wearing masks and dark clothing came to pick fights with people and we heard that some of them had weapons,” said Kevin Ng, a college student at the scene.
“I don’t know who the young men wearing masks were. We suspect they’re triad members, but it’s hard to say. What other kind of group would organise themselves to come attack us?”
Allegations have surfaced that some people were paid to disrupt the protests. A local radio station broadcast an audio clip yesterday in which a man, said to be a taxi driver, discussed a payment of 2,000 Hong Kong dollars (£160) to take part.
Demonstrators have flooded Hong Kong’s streets since 28 September over plans for a pro-Beijing committee to screen candidates in the first-ever direct election for the semi-autonomous Chinese city’s leader.
They also want Chief Executive Leung Chun-ying, the city’s Beijing-backed leader, to quit.
Mr Leung said yesterday that authorities had handled the protests with a “huge degree of tolerance” and added: “We cannot let this situation continue in the long term.”
Earlier yesterday, police removed some barricades at dawn to allow traffic through.
Police spokesman Steve Hui said later that officers would continue to trim the protest zone and warned that anyone challenging them could be arrested.