Oil prices slipped slightly on Monday amid concerns about a stalled global economic recovery and worries over renewed Libyan supply, but were supported by an impending storm which has disrupted U.S. oil production.

Brent crude LCOc1 was down 11 cents, or 0.2%, at $39.72 a barrel while U.S. West Texas Intermediate (WTI) crude futures CLc1 were down 12 cents, or 0.3%, at $37.21 a barrel by 1105 GMT.

In Libya, Khalifa Haftar committed to ending a months-long blockade of oil facilities, a move that would add more supplies to the market, although it was unclear if oil fields and ports would begin operations.

“The announcement that the blockade of Libyan oil export terminals may be about to end will add to the woes of OPEC+’s meeting this week,” said Jeffrey Halley, senior market analyst at OANDA.