Benchmark Brent Blend crude oil for August delivery erased earlier gains in a late session sell-off on London's International Petroleum Exchange but managed to hold above $30 a barrel to end 14 cents lower at $30.10. US light crude was 16 cents down at $31.90 a barrel.

Prices remain a long way above the ideal $25 a barrel level that Opec ministers say they are targeting after agreeing to a modest output increase last week.

Dealers shrugged off potentially bearish news that came after Tuesday's close when the American Petroleum Institute (API) reported US crude oil inventories rose last week. The API said US crude stocks for the week ended June 23 were up 2.25 million barrels to 291 million barrels. The increase was the first stock rise seen in the last seven weeks. A bullish run continued after the US Department of Energy on Wednesday reported a smaller crude stock build of 300,000 barrels, but eased off for crude to trade in a narrow range.