Oil fell on Wednesday after jumping for awhile above $40 a barrel, the highest since March, then retreating as doubts emerged about the timing and scale of a potential extension to the pact between Opec and its allies to cut crude supplies. Oil prices were also pressured as US refined product inventories surged in the week, raising concerns about demand.

“As product demand remains subdued, gasoline inventories showed a solid build, while distillates showed a mammoth one — despite refinery runs being over 3.6 million barrels per day below year-ago levels,” said Matt Smith, director of commodity research at ClipperData.

Saudi Arabia and Russia have a deal to extend oil output cuts by a month, but a policy meeting on Thursday rather than later in June is unlikely, sources said. Earlier in the session, oil fell when Bloomberg reported the Thursday meeting was in doubt.

The main obstacle to the meeting was how to deal with countries that have failed to make the deep supply cuts required under the existing pact.