Estimates by some election officials put the turnout at over 80%.

"The worst problem for most voters was the indelible ink": Simon Ingram reports

Official preliminary results are not expected until Saturday but some unofficial results may be issued as early as Monday.

Observers reported a relatively trouble-free process in most areas. But in a painful reminder of the tensions still affecting the country, the government said Khmer Rouge guerrillas had killed ten people in an attack just before the start of voting.

Queueing to vote

National Election Committee spokesman Samraing Kamsam told a news conference that voting in the remote northern area went ahead after the clash.

"The Khmer Rouge tried to destroy and disrupt the electoral process," he said.

Elsewhere, despite an election campaign marred by violence and criticised by the opposition and human rights groups as unfair, large crowds of voters turned out from early in the day.

There were no immediate reports of serious electoral misconduct.

Glenys Kinnock, the European Union's special representative at the elections, told the BBC: "You can always assume, in Cambodia, that intimidation has occurred.

"However, when we see the results I think that will be the best way of judging whether the people have been influenced by pressures put upon them.

"I suspect the result will show that the people will not have necessarily felt that the ruling party offered the kind of future that they would choose."

'Stiff challenge'

A BBC correspondent in Cambodia says the government of Hun Sen is facing a stiff challenge from opposition parties.

Hun Sen talks to Simon Ingram on BBC World (with voiceover translation)

In a BBC interview, the prime minister said the elections underlined the country's democratic credentials, and he pledged to surrender power within hours to the election victor if he were defeated.

Some observers say this pledge could be put to the test if the leading opposition parties have received support on the scale evident during their election campaigns.

Hun Sen: seeks to consolidate hold

The general election is the first since Prince Norodom Ranariddh was violently ousted from his position as First Prime Minister a year ago, and the BBC South East Asia Correspondent says Hun Sen needs a credible election to legitimise his hold on power.

Hun Sen's Cambodia People's Party has dominated the campaign and he is widely expected to win a majority.

But it is not expected to be by a big enough margin to rule alone, making a coalition the most likely outcome.

Poll "not a foregone conclusion": Caroline Gluck reports

Opposition groups and the human rights organisation Amnesty International accused Hun Sen's supporters of murder, kidnap and intimidation during the campaign.

Opposition confident

Prince Norodom Ranariddh: Main rival

The main challengers are the Funcipec Party, led by Prince Ranariddh, and the Sam Rainsy Party, led by a former finance minister of the same name.

Prince Ranariddh said he was pleased by the turnout and confident his party would win a fair vote. "I am very confident by the end of this day 80 to 90% of the voters will cast their ballots and FUNCINPEC will win," he said after voting.

Sam Rainsy said that although he had received reports of at least 30 minor polling irregularities, there was clearly a will for change in the country.

The BBC correspondent says a last major test of Cambodia's democratic credentials is the counting of ballots.