“For the second time this year, the people of Iraq have braved difficult conditions and the threat of violence to exercise their vote,” a spokesman for Mr. Annan said in a statement, referring to widely praised national elections held in January.

The referendum was “an important opportunity for the Iraqi people to express their political views,” the spokesman said.

The Secretary-General paid tribute to the courage of the people of Iraq and praised the country's Independent Electoral Commission, as well as the thousands of Iraqi election workers and monitors, for having “organized and carried out the referendum in such challenging circumstances.”

Although preliminary official results are unlikely to be available for at least several days while ballots are counted, the Secretary-General stressed that whatever the outcome, the referendum offers an opportunity for all Iraqis to move away from violence and to unite in a spirit of national reconciliation to build a democratic, unified and prosperous Iraq.

“The United Nations will continue to do all it can to help the Iraqi people to that end,” the spokesman said.