Gates also said he saw "some chance of a modest acceleration" in the pace of US troop withdrawal from Iraq.
|Gates said that one combat brigade might come out of Iraq ahead of schedule [AFP]
The US defence secretary told reporters that perhaps one combat brigade would come out of Iraq ahead of schedule, though he did not give a precise timetable.
The number of US combat brigades in Iraq had been scheduled to go down to 12 from the current 14 in January, when Iraq goes to the polls in its first national elections since 2005, but Gates said the number could fall to 11 instead.
There are about 130,000 US troops in Iraq, and combat troops are due to withdraw by the end of August next year, part of a plan for a complete pullout by the end of 2011.
Iraq's Kurds voted Barzani back into power on Wednesday.
Barzani took 69.9 per cent of the ballot, while the two-party ruling alliance, including Barzani's Kurdistan Democratic Party (KDP) and Iraqi President Jalal Talabani's Patriotic Union of Kurdistan (PUK), received 57 per cent of the parliamentary vote.
The two factions have dominated the region's politics for decades and have been in power since the region became semi-autonomous in 1991.
The Kurdish regional administration's aggressive strategy for exploiting their own oil and gas fields has led them into conflict with the Iraqi oil ministry.
The Kurds have asserted their right to the oil-producing Kirkuk region and other disputed areas lying outside the current borders of their enclave.