PHNOM PENH, Cambodia — Cambodia's opposition party has escalated its challenge to the country's election results, claiming it won a majority of National Assembly seats. The ruling party earlier made its own claim of victory in the Sunday polls.

Yim Sovann, spokesman for the opposition Cambodia National Rescue Party, said Wednesday that based on reports from party workers and election observers, his party had won at least 63 of the assembly's 123 seats. Party leader Sam Rainsy made the same claim late Tuesday.

Prime Minister Hun Sen's Cambodian People's Party earlier claimed it had won 68 seats to the opposition's 55. Provisional official results support the ruling party's projection.

The opposition has already called for an investigation of voting irregularities, including registration problems that could have disenfranchised more than a million people.