By Guy De Launey
BBC News, Phnom Penh
Buddhist monks and riot police have been involved in a violent confrontation in Cambodia's capital.
Police say the monks brought stones to use as missiles
The monks were trying to draw attention to allegations of mistreatment of the Kampuchea Krom minority, who are ethnic Cambodians living in Vietnam.
They were attempting to deliver a petition to the Vietnamese Embassy in Phnom Penh when police officers blocked their way.
Human rights workers claim the police beat the monks with batons.
The violence started after about 50 orange-robed monks arrived at the Vietnamese Embassy and staged a sit-down protest.
The situation deteriorated as riot police ordered the monks to move on.
The authorities allege that the monks tried to storm the embassy and had brought stones to throw at the police.
Several members of each side were injured, none of them seriously.
The monks had been protesting about the treatment of ethnic Cambodian colleagues in Vietnam.
Their petition asked for the release of a monk who has been jailed on charges of "undermining national unity".
They also demanded the return of Vietnamese territory which they claimed belonged to Cambodia.
It is a sensitive topic for the Cambodian government.
Its links with Vietnam date back to 1979 when Vietnamese-backed troops ousted the Khmer Rouge from power.
But many Cambodians dislike their larger neighbour and resent the loss of territory over the years, which includes modern day Ho Chi Minh City.
Some Buddhist pagodas have become rallying points for protests on the issue.