[SYDNEY] Oil headed for the longest run of monthly advances in more than five years as Opec delegates prepared to meet this week in Vienna to assess output.
Futures in New York are up about 8 per cent in May, rising for a fourth month. Libya's Petroleum Facilities Guard captured a town near the Es Sider and Ras Lanuf oil-loading terminals after fierce clashes with Islamic State militants.
Oil has surged since slumping to a 12-year low in February on signs the worldwide surplus is easing amid declining production from the US to Nigeria.
Opec is unlikely to reach any agreement to limit output when it meets Thursday as the group sticks with Saudi Arabia's strategy of squeezing out rivals, according to analysts surveyed by Bloomberg.
West Texas Intermediate for July delivery was at US$49.49 a barrel on the New York Mercantile Exchange, up 16 US cents at 9:02 am Sydney time. There was no settlement Monday because of the US Memorial Day holiday. Trades will be booked Tuesday for settlement purposes.
Brent for July settlement, which expires Tuesday, rose 44 US cents, or 0.9 per cent, to close at US$49.76 a barrel on the London-based ICE Futures Europe exchange on Monday. Prices are set for a fourth-monthly increase, also the longest streak since 2011.