Oil markets jumped on Monday as Iraqi forces entered the city of Kirkuk, taking territory from Kurdish fighters and raising concerns over exports from OPEC's second-largest producer.
"We're seeing increased geopolitical tension in the Middle East providing support in the market today, namely in Iraqi Kurdistan, and some uncertainty around Iran," said Anthony Headrick, energy market analyst at CHS Hedging LLC in Inver Grove Heights, Minnesota.
Iraq's Kurdistan briefly shut down some 350,000 barrels per day (bpd) of production from major fields Bai Hassan and Avana due to security concerns. Iraq launched the operation on Sunday as the crisis between Baghdad and the Kurdish Regional Government (KRG) escalated. The KRG voted for independence in a Sept. 25 referendum.
U.S. West Texas Intermediate crude ended Monday's session 42 cents higher at $51.87 per barrel. Earlier in the day, it traded as high as $52.37.
International Brent crude futures rose 66 cents, or 1.2 percent, to $57.83 per barrel by 2:29 p.m. ET (1829 GMT), after trading as high as $58.47.