Cambodian Prime Minister Hun Sen's ruling party claimed it had sealed a landslide victory in parliamentary elections Sunday that were expected to usher in a new term for the former Khmer Rouge soldier who has ruled for 23 years.

Hun Sen's popularity at the polls was buoyed by a surge of nationalism amid a tense border dispute with neighboring Thailand.

The 57-year-old Hun Sen's reputation as a strongman served him well in the campaign, with voters rallying around the leader as Cambodian troops faced off with Thai soldiers for a second week at a disputed 11th century Hindu temple.

Just hours after polling stations closed, the ruling Cambodian People's Party appeared to be "leading everywhere" and estimates from party agents nationwide indicated a sweep of more than 83 seats in the 123-seat lower house, said party spokesman Khieu Kanharith. Such a result would strengthen the party's dominance and give it a two-thirds majority in the 123-seat lower house.

"We can claim a landslide victory. It is certain," the spokesman told The Associated Press, adding that vote counting had been completed in most constituencies.

Thun Saray, head of the Cambodian election monitoring group Comfrel, said it was "early to declare victory but the trend shows that CPP is winning." Official results were expected later in the week.

In power since 1985, Hun Sen is Asia's longest-serving leader. He was expected to win the vote even before the military standoff escalated earlier this month. But patriotic passions over Preah Vihear temple and Hun Sen's firm stance against Thailand have swayed many undecided voters in his favor, analysts say.

"Everybody now supports the government because this is a national issue," said Kek Galabru, a prominent Cambodian human rights activist and election monitor. "More people will vote for (Hun Sen) to give him more power to deal with Preah Vihear."

Chan Sim, a 72-year-old in the capital, said he cast his ballot for Hun Sen's ruling party "because of its good leadership and ability to keep unity."

Hun Sen had voiced little doubt that his party, which held 73 assembly seats during the past five-year term, would return to power for another five years.

"I wish to state it very clearly this way: No one can defeat Hun Sen," the prime minister said earlier this year.

Hun Sen has been at the center of Cambodian politics since 1985 when he became the world's youngest prime minister at age 33. He has held or shared the top job ever since, bullying and outfoxing his opponents.

Sunday's voting was the fourth parliamentary election since the United Nations brokered a peace deal in 1991 meant to end decades of civil unrest that included the 1975-79 genocidal reign of the Khmer Rouge.

When Vietnam's army drove the Khmer Rouge from power in 1979, Hun Sen at age 27 was named foreign minister and later prime minister in a single-party Soviet-style regime.

The first election was held in 1993 and supervised by the United Nations. The royalist Funcinpec party won but was strong-armed into forming a coalition with Hun Sen, who later wrested full power in a 1997 coup.

Repeated allegations of vote fraud have failed to dent the dominance of the ruling party, which has wooed Cambodia's poor majority with populist policies and dotted the countryside with schools, temples and roads.

Internationally, he has faced criticism for alleged corruption and human rights abuses. But Hun Sen argues that his tenure has ushered in peace and stability after the Khmer Rouge's rule, during which an estimated 1.7 million people died.

A former Khmer Rouge soldier, Hun Sen has embraced free-market policies that have recently made Cambodia's economy one of the fastest growing in Asia, expanding at 11 percent in each of the past three years.

The opposition Sam Rainsy Party, which held 24 seats in the lower house of Parliament, campaigned for an end to alleged government corruption, greater attention to human rights and the country's poor. More than a third of Cambodians live on less than $1 a day.

An irate Sam Rainsy claimed that some 200,000 registered voters in the capital, Phnom Penh, where the opposition is strongest, were unable to cast ballots because their names were left off voter lists. He demanded a new vote in the city.

National Election Committee chief Tep Nitha dismissed the fraud allegation, saying voters had been told to check last year if their names were on voting lists.

This year's election campaign was upstaged by the military standoff with Thailand.

The controversy revolves around less than two square miles of land that has been in dispute since French colonialists withdrew from Cambodia in the 1950s.

The International Court of Justice awarded the temple site to Cambodia in 1962, but anger flared in Thailand last month after Thai Prime Minister Samak Sundaravej backed Cambodia's successful bid for the temple to be listed as a U.N. World Heritage Site.

Thailand sent troops to the border July 15 after Thai anti-government demonstrators assembled near the temple. Cambodia responded by sending its own troops to the border.