Cambodia's main opposition party on Monday rejected election results given by the government, which said long-serving Prime Minister Hun Sen's party had won, and called for an inquiry into what it called massive manipulation of electoral rolls.
The Cambodia National Rescue Party (CNRP), whose campaign was given a boost by the return from exile of leader Sam Rainsy, said it wanted an investigation committee set up with representatives from the political parties, the United Nations, the election authority and non-governmental organisations.
"There were 1.2 million to 1.3 million people whose names were missing and could not vote. They deleted our rights to vote, how could we recognise this election?" Sam Rainsy told a news conference.
"There were ghost names, names only on paper, over a million people that may been turned into votes. We cannot accept this result," he said.
The CNRP said the committee should report back by Aug. 31.
On Sunday, the government said Hun Sen's Cambodian People's Party (CPP) had won 68 seats in the 123-seat parliament to the CNRP's 55. Even that would have been a huge setback for the authoritarian leader, who has been prime minister for 28 years.
The CPP, backed by a compliant Cambodian media and with superior resources, had been confident of victory.
Analysts, however, had predicted a reduction in its majority after the merger of two main opposition parties, as well as the return of Sam Rainsy.
The CPP had 90 seats in the outgoing parliament and the parties that united to form the CNRP had 29, with minor parties holding the remaining four.
Sam Rainsy called for calm after the government gave the results late on Sunday and thanked the Cambodian people for "their dignified participation in this election".
He appealed to his youthful supporters not to cause trouble. "We call for peace and reconciliation," he said.
Voting on Sunday, like the campaign itself, was for the most part peaceful, although a crowd angered by alleged irregularities set fire to two police cars outside a polling station in the capital, Phnom Penh.
The United Nations organised an election in 1993 that put Cambodia on a rocky path towards stability after decades of turmoil that included the 1975-79 "Killing Fields" rule of the communist Khmer Rouge.
Under Hun Sen, a former junior commander in the Khmer Rouge who broke away during their rule, Cambodia has been transformed into one of Southeast Asia's fastest-growing economies, helped by garment exports plus aid money and investment from China.
But economic growth has been accompanied by a rise in social tension over poor factory conditions and rural land rights in a
country of 14 million people where a third of the people live on less than 65 U.S. cents a day.