The UN chief said progress had been made but there was further to go
The UN Secretary-General, Ban Ki-moon, has made a surprise visit to Iraq to congratulate voters there on the outcome of nationwide local elections.
After talks with political leaders in Baghdad, Mr Ban said the vote showed how far Iraq had come.
However, he said there was still a long way to go before Iraqis could claim to have "genuine freedom and security".
Allies of Prime Minister Nouri Maliki swept to victory in Baghdad and key provinces in last Saturday's poll.
The United Nations played a key role in organising the elections - seen as a test of stability before a general election, due later this year.
The BBC's Jim Muir, in Baghdad, says that like everyone else, the UN is relieved that both the polling day itself and the announcement of the results passed off with virtually no violence at all.
Election commission preliminary results announced on Thursday showed Mr Maliki's State of Law coalition had made spectacular gains in southern Shia areas.
PM Maliki's coalition won by huge margins in Baghdad and Basra
The coalition won 38% of votes in Baghdad and 37% in Iraq's second city Basra - curbing the previous dominance of rival Shia parties.
Meanwhile, the once-dominant Sunni Arabs regained political power in other parts of the country - having boycotted the 2005 election.
There were fears of violence in the mainly Sunni flashpoint province of al-Anbar, where tribal leaders had threatened to take up arms over the result.
In the event, they came in just half a percentage point behind another Sunni party to which they are allied.
2003: US appoints Governing Council
2004: Governing Council elects interim government
Aug 2004: National conference elects interim national assembly
Jan 2005: First general elections for transitional national assembly and provincial councils - Sunnis boycott vote
Dec 2005: General elections for first full-term government and parliament
Jan 2009: Elections for provincial councils - key test of security gains
Late 2009: General elections due
Mr Ban was expected to hold talks with Mr Maliki as well as Iraqi President Jalal Talabani while in Baghdad.
He will "reiterate the UN's commitment to the country", and "above all congratulate the Iraqi people on the success of largely violence-free elections", UN spokesman Said Arikat told the AFP news agency.
The election was an extraordinary achievement in a country that has been wracked by violence for the last nearly six years, our correspondent says.
Healthy and peaceful political competition, and change through the ballot box, have become the name of the game, he adds.
Just over half of Iraqis voted in Saturday's election, lower than some had predicted.
Final results are not expected to be known for weeks.