Polls have closed in Iraq where people have been voting on a new constitution.
Large numbers of Sunni Arab voters turned out in Mosul
Conditions in many areas were described as calm, in contrast to the violence of January's election when insurgents carried out dozens of lethal attacks.
The worst incident occurred near the Iranian border where three soldiers died in a roadside bomb, while several Baghdad voting centres came under fire.
Election officials say it will take three to four days to count the "Yes" and "No" votes of up to 15.5m Iraqis.
BBC Middle East analyst Roger Hardy says optimists believe the new charter will bring stability and end violence, while pessimists fear the break-up of the country.
US President George W Bush said the vote was "a critical step forward in Iraq's march toward democracy".
US Secretary of State Condoleezza Rice told the BBC Iraqis were "investing their future" in the political process.
"Every time the Iraqi people have been given an opportunity to express themselves politically, they have taken it," Ms Rice said.
As the polls closed, celebratory gunfire broke out in several areas of Baghdad.
Voters had flocked to polling stations throughout the day.
"This is all wrong. I said 'No' to a constitution written by the Americans," one vote, Jilan Shaker, told the Associated Press news agency.
Another said: "It's history here, making history here. That's very good."
In the southern city of Basra, a man said he was voting "Yes" "to end the occupation" - a view shared on both sides of the sectarian divide, says the BBC's Paul Wood there.
Initial reports suggest turnout has been high in Shia areas, while voting in the predominantly Kurdish north was thought to be lighter than expected.
Sunni Arabs - who largely boycotted January's vote - were reported to have come out in force, many of them saying they wanted the charter to fail.
"I just voted 'No' because we Sunnis must show we have our say," said a young voter in Falluja.
Sunni areas of Baghdad and a number of cities including Falluja, Baquba and Mosul in the north all saw high turnouts. But the electoral commission said more than one third of the polling stations had not opened in several cities in Anbar where US-led forces have been fighting the insurgency.
A commission spokesman, Saadallah al Rawi, said turnout was low in five of the province's cities, particularly Ramadi, where there was continued violence.
CONSTITUTION'S KEY POINTS
Iraq to be federal, parliamentary democracy
Official languages to be Arabic and Kurdish
Official religion to be Islam but religious freedoms guaranteed
Equal rights for all
Elections every four years
Insurgents targeted an Iraqi military convoy near the Iranian border east of Baquba, killing three soldiers, and at least one civilian was killed and six were injured in attacks on polling stations in Baghdad.
If voters in three of Iraq's 18 provinces muster a two-thirds majority against the constitution, it will fail.
The Sunnis are dominant in four provinces and so therefore effectively hold a power of veto if they turn out in large numbers to vote against it.
If the text passes, it will provide the basis for parliamentary elections.