"Immediately after her arrival in Erbil, she met with Mr Barzani on political issues, the upcoming (general) elections and relations between the Kurdish regional government and the United States," said the official.

The Iraqi parliament failed on Wednesday to agree on a new electoral law, making it difficult to hold the elections by mid-January, at a crucial stage when US forces are preparing to withdraw.

In Washington, US undersecretary of defence for policy Michele Flournoy argued before Congress that the election uncertainty could have consequences for the US withdrawal.

The most difficult issue remains the disputed region of Kirkuk.

Kurds say they are the majority in this province of 900,000 inhabitants, and want to annex it to their autonomous region, while Arabs and Turkmen accuse them of settling en masse to change the demographic balance.

Barzani dismissed on Thursday any special arrangements for the region.

"We refuse the adoption of a special election law for Kirkuk. We don't accept a distribution of seats according to a quota decided in advance," the Iraqi Kurdish leader said.

"Elections in Kirkuk must be held simultaneously with the rest of the country and we refuse the establishment of electoral constituencies in the governorate on an ethnic basis," he added.

In Baghdad on Saturday, Rice met Iraqi Foreign Minister Hoshyar Zibari and visited the headquarters of the ministry whose offices were destroyed by a truck bomb on August 19.

While pointing the finger at Syria, Iraq has demanded international investigators determine who was behind the attack, which killed about 100 people.