A nationwide security clampdown virtually emptied city streets and highways across Iraq today on the eve of a referendum on a new constitution.
Iraqi officials moved ballots into polling centres, but most shops were shuttered and there was little traffic.
A "Yes" vote is widely forecast, with religious leaders of the Shia majority and Kurdish parties urging approval. But interviews with dozens of Iraqis in numerous towns revealed mixed feelings, not only in the disaffected Sunni Arab minority.
US troops say they will keep in the background, away from polling stations, to limit accusations from some Iraqis that the constitution is being imposed under the duress of occupation.
But formidable firepower is in reserve to combat insurgents and protect the transport of ballot papers. Security measures may be working, with only limited violence in the past 48 hours.
An overnight curfew took effect yesterday and private vehicles are banned from the roads entirely from today night to Sunday morning during a special four-day public holiday.
Hussein al-Hindawi, head of the Independent Electoral Commission, said ballots had been held under guard but would be moved to polling stations around the country on Friday.
"We put the materials in special safe storehouses near the polling stations, and today we are going to move them so they will be ready by tomorrow," Mr Hindawi told Reuters.
The constitution is part of Washington's plan to establish a stable democracy in Iraq and eventually withdraw US troops.
Sunni Arab militants, angry at America and fearing the new constitution will sideline them in favour of the Shia majority and its Kurdish allies, have staged a relentless series of car bombings, suicide attacks and kidnaps that has pushed Iraq towards chaos and killed thousands of civilians.
Negotiations aimed at winning Sunni support for the constitution scored a success this week when at least two main Sunni political groups opted to back the charter in exchange for a promise that amendments would be considered after the vote.
But other Sunnis have remained steadfastly opposed and militants have since turned their fury on the first party which voiced support for the document, attacking at least one of its offices and distributing leaflets accusing it of collaboration.