ARBIL, Iraq (Reuters) –
The U.S. defense secretary flew to Iraq's Kurdish region on Wednesday to help defuse tensions with the central government over land and oil that U.S. and Iraqi officials fear could spill into violence.

Defense Secretary Robert Gates met Masoud Barzani, former guerrilla leader and president of Iraq's largely autonomous Kurdish region, whose Arbil-based Kurdistan Regional Government is at odds with Baghdad's Arab-led government.

The dispute over land, hydrocarbons and power between Kurdistan in Iraq's north and the central government in Baghdad has ratcheted up, leading to fears of possible clashes between Iraqi troops and Kurdish Peshmerga forces.

There are fears that Iraq's waning insurgency might style itself as an Arab bulwark against Kurdish encroachment.

U.S. Army General Ray Odierno, the top U.S. commander in Iraq, on Tuesday called the dispute the "number one driver of instabilities" in the country.

The Pentagon did not immediately provide an account of the talks between Gates and Barzani.

Gates, who landed in Iraq on Tuesday on a previously unannounced visit, offered U.S. help on Tuesday in resolving disputes over Kurdish claims to disputed territories.

"We are ... willing to assist in resolving disputes over boundaries and hydrocarbons, disputes that require continued commitment to the political process by word and deed," he said.

Gates' visit comes as Iraqi officials prepare to announce the results of weekend presidential and parliamentary polls in Kurdistan which, despite an unprecedented challenge from opposition groups, are seen as unlikely to unseat Barzani from the presidency and shatter his allies' grip on power.

There is some hope that Iraqi and Kurdish officials may be more ready to make concessions now that Kurdish electioneering, characterized by fiery rhetoric about disputed areas, is over.

At the heart of the feud is the oil-producing region of Kirkuk, which Kurds consider their ancestral homeland and want to make part of their semi-autonomous Kurdish enclave.

The city's Arabs and Turkmen fear Kurdish hegemony.

Potential Iraqi purchases of U.S. weaponry was also an important point in Gates' visit, his 10th to Iraq as defense secretary, as Iraqi forces take the lead for security in Iraqi cities and towns following the June 30 U.S. combat troop withdrawal from urban bases.

On Tuesday, Gates said the transition from U.S. to Iraqi military primacy in urban areas was going well. He met with Prime Minister Nuri al-Maliki and the heads of Iraq's interior and defense ministries.

(Writing by Mohammed Abbas: Editing by Missy Ryan and Alison Williams)