Cambodian opposition supporters have clashed with police in the capital Phnom Penh after they attempted to re-open a protest site, in defiance of a ban on political gatherings.
Dozens of people were hurt in the clashes, and three opposition members of parliament were detained after the protest on Tuesday.
The skirmishes near the capital's Freedom Park were the latest unrest since a disputed election a year ago which the government of long-serving Prime Minister Hun Sen said it won despite surprising opposition gains.
The park was the only place in Phnom Penh where protests were allowed until it was closed in January after supporters of the opposition Cambodia National Rescue Party (CNRP) held a protest there aimed at toppling Hun Sen.
Phnom Penh municipality spokesman Long Dimanche said three opposition politicians including Mu Sochua, a party leader, were taken into police custody after their supporters attacked guards who prevented them from re-opening the park.
"The opposition party led a protest that is illegal causing disorder and violence," said Long Dimanche, adding that 37 city security guards were injured.
Chuon Narin, deputy chief of Phnom Penh municipal police, said authorities "did not arrest opposition lawmakers" but detained "anarchist demonstration leaders who led a violent protest."
It was not immediately clear when they would be released.
Teargas and batons
A Reuters news agency reporter at the scene said the guards attacked the protesters with batons after the activists tried to string up banners on a barbed wire fence surrounding the park.
That sparked retaliation from the crowd, some of whom beat guards, according to the Reuters witness. Riot police dispersed the protesters with teargas.
The opposition said the election in July last year was rigged to allow Hun Sen to stay in power and is calling for him to step down, or for a re-run of the vote.
Hun Sen and his government have dismissed accusations of vote rigging.
Over the past year, the veteran leader has faced some of the biggest protests seen in Cambodia so far, with factory workers from a multi-billion dollar apparel industry linking up with the political opposition to demand better pay.