The Niger Delta Avengers, a rebel group that has attacked numerous oil facilities in Nigeria, rejected a truce offer with officials and claimed they hit a new target.
The disruptions have slashed output in OPEC member Nigeria from 2.2 million barrels a day to 1.6 million barrels a day.
US benchmark West Texas Intermediate for July delivery advanced 87 cents to USD 51.23 a barrel on the New York Mercantile Exchange.
US inventory data today confirmed a tightening market picture, with US commercial stocks dropping by 3.2 million barrels for the week ending June 3, according to the Department of Energy.
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Analysts said US inventories could fall further as the world's biggest economy advances towards peak summer driving season and refineries ramp up gasoline production.
"Increasing refinery utilization in the US is now starting to have an impact in inventories as we're seeing draws," said Houston energy consultant Andy Lipow.
"I expect this trend is going to continue over the rest of the summer as refiners have finished with their maintenance season, increasing demand for crude oil.