Rice visits Iraq's volatile north

US Secretary of State Condoleezza Rice has made an unannounced visit to the volatile northern Iraqi city of Kirkuk.

US officials said she would use her trip to encourage Iraqi leaders to seek political reconciliation.

"It is an important province for the future of Iraq, for a democratic Iraq," she said at talks with local leaders.

Analysts say the Bush administration is frustrated that recent security gains in the oil-rich region have not been accompanied by political advances.

Kirkuk is home to a volatile mix of Kurds, Sunni and Shia Arabs and Turkmen, all of whom dispute its historical identity.

"It truly is the crossing point for every one of Iraq's ethnicities, every one of Iraq's religions and sects," said Ms Rice's leading adviser on Iraq, David Satterfield.

"Kirkuk is often identified as a flashpoint for the future of Iraq. We see a logjam being broken here," he said.

Referendum delayed

Ms Rice first visited members of a reconstruction unit in the city and then held talks with provincial politicians, where she underscored recent moves towards unity.

Earlier this month, Sunni Arabs ended a year-long boycott of the provincial government under a deal with Kurdish parties that gave them a more equal share of power.

The Kurds want to see the province of which Kirkuk is the capital attached to their own autonomous area in the north - an idea resisted by many Arabs and Turkmen.

Under the Iraqi constitution, a referendum on the issue was supposed to take place by the end of this year but preparations have been delayed.

Many major divisive issues, such as a law to allocate the country's oil resources, have still not been resolved.

Ms Rice's visit comes just hours after about 300 Turkish troops reportedly crossed into northern Iraq to target Kurdish separatist rebels.

She is expected to hold talks with Iraqi leaders in the capital, Baghdad later on Tuesday.