PHNOM PENH, Cambodia — Cambodia's opposition said Sunday that it would boycott the opening session of parliament and carry out more street protests even though the election victory of Prime Minister Hun Sen's ruling party has now been officially ratified.
Sam Rainsy, leader of the opposition Cambodia National Rescue Party, told reporters that his party would not take part in any form of government as a matter of principle until there was an independent investigation of alleged election irregularities.
Earlier Sunday, the government-appointed National Election Committee ratified results giving Hun Sen's Cambodian People's Party 68 seats in the National Assembly, and the opposition party 55.
Parliament has to convene within 60 days of the July 28 election.
Sam Rainsy said the opposition would hold continuous public demonstrations from Sept. 15-17, which might include rallies or marches, to press its demand for a probe.
Hun Sen has ruled Cambodia for 28 years and remains firmly in control, although the opposition won significantly more seats than it had in the past.
The opposition has claimed it would have won the majority of seats had the election been fair, but its legal challenges were rejected. About 20,000 opposition supporters gathered Saturday in Phnom Penh, the capital, to cheer their leaders' demands for an investigation of what their leaders said was vote tampering and widespread voter disenfranchisement.
"As long as the ruling party does not accept the truth to be exposed, and does not accept to render justice to the Cambodian people through voting, we will not participate in any form of government or any form of arrangement with the ruling party, because it is a matter of principle," Sam Rainsy said Sunday. "We're never going to compromise our principles."
He suggested that if Hun Sen's party proceeded to rule with a single-party parliament and no probe of the election results, it would be rejected by both the Cambodian people and the international community, so that "Cambodia will be really headed for trouble, for instability ..."
It was not clear how long a boycott of parliament would last. Deputy opposition leader Kem Sokha specified it would apply to the opening day of the new National Assembly, while Sam Rainsy's remarks implied it would be open-ended.
After previous elections, opposition members have boycotted initial assembly sessions and later been admitted into the body. But a boycott could mean the opposition loses out on parliamentary leadership positions such as committee chairmanships.
While the opposition previously seemed to hope it could invalidate some of the election results, it now may be seeking a show of strength mostly to pressure the ruling party to give up some of the leadership positions.
David Chandler, a leading Cambodia scholar, said it would be wise for the opposition lawmakers to simply take up the 55 seats they won rather than risk losing their say in government.
"I can sympathize with the CNRP, but I think they're being very unrealistic in their demands for power," he said.
Sam Rainsy said there would be "a series of demonstrations," the first of which is to begin Sept. 15 and continue until Sept. 17. He said the demonstrations could take the form of sit-ins or marches, but that the party had not yet decided the specifics.
Asked if he was worried that drawn-out protests would lose steam, he said he had "no concern. We have been in touch with the population, and the population is very frustrated."
Previous plans for protests stirred fears of violence, especially because of the government's deployment of troops and armored vehicles in Phnom Penh days after the election. Hun Sen has a reputation for dealing harshly with opponents.
Hun Sen has a record of cracking down on the opposition after previous elections, but the surprising strength of the opposition's results, also reflected in a close popular vote, has raised speculation that he may try to play the reform card this time around to placate critics and accommodate the public will.
"The Cambodian People's Party understands the message that the people expressed through their ballots for the need for the new government to undertake reforms," said Khieu Kanharith, Hun Sen's information minister and spokesman for his ruling party. "We'll undertake thorough reforms for the sake of our country."