Brent crude for August eased 15 cents to USD 114.91 in mid-morning trade, after rallying to USD 115.06 in London, its highest since early September.
US benchmark West Texas Intermediate for July delivery rose 26 cents to USD 106.69. "Oil saw support from the risk of conflict in Iraq disrupting oil supplies, as the US said it would send military advisers to the country," Singapore's United Overseas Bank said in a note. The militants have captured swathes of Iraq's north but have yet to directly threaten the key oil-producing region in the south.
The crisis has rocked the global oil market because Iraq is the second-biggest producer within the 12-nation Organisation of Petroleum Exporting Countries (OPEC). The country has more than 11 per cent of the world's proven resources and produces 3.4 million barrels a day.
Aside from concerns about Iraq, French bank Credit Agricole said "the market today should be relatively quiet heading into the weekend" with no significant data release and the conclusion of a key US central bank meeting.