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Cambodia's ruling party coasted to victory in Sunday's general election - a result rights groups slammed as illegitimate and that the Trump administration described as "flawed."

A government spokesman told The Associated Press that Prime Minister Hun Sen's Cambodian People's Party (CPP) had topped the polls. He did not say how many of the of the 125 seats in the National Assembly the CPP had captured, but preliminary totals broadcast on state television showed that the party had won at least 70 percent of the vote in each of the country's 25 provinces. Under the election's system of proportional representation, the party would likely grab more than 100 seats.

Although 20 parties contested the election, the only one with the popularity and organization to mount a real challenge, the Cambodian National Rescue Party (CNRP), was dissolved last year by the Supreme Court in a ruling generally seen as political in nature.

Local and foreign rights groups, along with several Western governments, had agreed that the election would not be credible.

In a statement, White House Press Secretary Sarah Sanders said the vote was "neither free nor fair and failed to represent the will of the Cambodian people. The flawed elections ... represent the most significant setback yet to the democratic system enshrined Cambodia's constitution, and substantially erode Cambodia's achievements in promoting political reconciliation and economic growth."

Sanders added that the Trump administration would consider its response to the election "and other recent setbacks to democracy," including an expansion of visa restrictions announced by the White House in December.

Sen. Dick Durbin, D-Ill., tweeted: "[Hun Sen] and his thugs threatening the voters of #Cambodia does not make a free and fair election."

Charging that the polls were neither free nor fair, the disbanded CNRP's former leaders had urged people not to vote in what was dubbed a "Clean Finger" campaign because those who did cast ballots had to dip a finger in indelible ink, a practice meant to thwart multiple voting.

According to detailed totals released by the state National Election Committee, more than 6.8 million registered voters, or 82.2 percent, cast ballots.

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Cambodian voters show off inked fingers outside a Phnom Penh polling station. (Copyright 2018 The Associated Press. All rights reserved.)

The figure, if correct, would suggest that the promotion by opposition forces of a poll boycott was ineffective. In the last general election in 2013, voter turnout was 6.6 million, or 68.5 percent of 9.7 million registered voters.

Hun Sen said on his Facebook page before the results were announced that he welcomed the big turnout, and congratulated his countrymen for exercising their right to vote.

Opposition forces, who had already judged the polls not to be free or fair because of the exclusion of the only credible challenger, can point to two reasons for the alleged failure of the boycott movement.

In rural areas where the majority live, the failure to vote — signified by having no fingers dipped in indelible ink — made voters subject to retaliation by local officials who carry out civic functions, such as land registration. There had been reports during the campaign of threats against anyone who planned to boycott the vote.

Voters in Phnom Penh, Cambodia's capital and an opposition stronghold, were less susceptible to such threats because of their higher visibility and safety in numbers. However, according to the election committee, even there the turnout was about 80 percent.

Doubts are also likely to be raised about the actual turnout figures because several established poll-watching groups — as well as contingents from the United States and the European Union — declined to take part because they felt the polls were not legitimate. One of the bigger Cambodian groups participating in poll-watching was led by one of Hun Sen's sons.

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Polling officials empty ballot boxes at a Phnom Penh polling station Sunday. (Copyright 2018 The Associated Press. All rights reserved.)

Following the election, exiled opposition leader Sam Rainsy, who had earlier urged Cambodians not to vote, called for peaceful protests, calling it "a sham election with a foregone conclusion."

Speaking from south of Paris in Freteval where he lives, Sam Rainsy told The Associated Press that "it is a meaningless victory because [Hun Sen] won without any real challenger ... prior to the election he dissolved the only credible opposition party."

The CPP was alarmed by the results of the 2013 election, when the race was close enough for the opposition to claim that it would have won had it not been for manipulation of the voter registration process.

Along with fracturing the political opposition — including pressuring Sam Rainsy into exile and jailing his successor, Kem Sokha — Hun Sen's government also silenced critical voices in the media. Over the past year, about 30 radio stations shut down, and two English-language newspapers that provided serious reporting were gutted, one forced to close and the other put under ownership friendly to the government.

Just ahead of the polls, the government ordered the temporary blocking of 17 websites, citing regulations prohibiting media from disseminating information that might affect security. The blocked websites included those of the U.S. government-funded Voice of America as well as local media.

Hun Sen, whose 33 years in power make him among the world's longest-serving national leaders, promised peace and prosperity at a rally on the last day of campaigning on Friday, but attacked the opposition's boycott call and called those who heed it "destroyers of democracy."

Hun Sen, 65, has said he intends to stay in power for at least two more five-year terms.

He was a member of the radical communist Khmer Rouge during its successful five-year war to topple a pro-American government, then defected to Vietnam during Khmer Rouge leader Pol Pot's 1975-79 genocidal regime that left nearly 2 million Cambodians dead. He became prime minister in 1985 in a Vietnamese-backed single-party communist government and led Cambodia through a civil war against the Khmer Rouge, which eased off with the 1991 Paris Peace Accords that also installed a democratic political framework.

The Associated Press contributed to this report.