PHNOM PENH (Reuters) - Two foreigners were among eight people arrested by Cambodian police on Monday in Phnom Penh for protesting the jailing of a group of human rights workers and an election official on what demonstrators said were politically-motivated charges.
Anti-riot officers carrying batons and shields set up roadblocks to prevent some 40 people protesting outside the prison holding those jailed.
Eight demonstrators include protesters from two rights groups Licadho and Sahmakum Teang Tnaut were bundled into police vans. One Swedish and one German man were among those detained.
Tension is running high as a string of legal cases filed against prominent members of the country's main opposition party weaken its chances of wresting power from self-styled strong man Prime Minister Hun Sen at the next general election in 2018.
Sam Rainsy, the leader of the opposition Cambodia National Rescue Party (CNRP), is in exile to avoid prison on charges that were reactivated last year and for which he had previously received a royal pardon.
Rainsy's deputy Kem Sokha, CNRP's acting president in Rainsy's absence, is facing charges for defamation and procurement of prostitution after recordings of a telephone conversation purportedly between Sokha and a woman were leaked.
Six other people - including a United Nations employee - allegedly paid the woman to deny she had a relationship with Sokha, and are facing trial on bribery charges. The UN worker has not been detained.
Rights groups have accused the government of using the legal system to neutralize the opposition and give Hun Sen the advantage in a vote that could be his biggest challenge in more than 30 years in power.
Government spokesman Keo Remy said the protesters, who wore black shirts in support of the jailed activists, had been told in advance that their planned protest could not proceed.
"The situation may become chaotic," Keo Remy told reporters, adding the government was concerned the actions of some civil society groups could cause civil war.
"I don't want to see Cambodia plunged into a situation like the Middle East's," he said.
A strong performance by the CNRP in the 2013 election sparked a year-long parliamentary crisis in Cambodia. The CNRP boycotted parliament after accusing the government of stealing that election.
A political truce between the two parties ended after a year in 2015.
(Reporting by Prak Chan Thul; Editing by Simon Webb and Ryan Woo)