US crude was off 13 cents at $65.22 by 1151 GMT. London Brent crude was off 6 cents at $64.30.

Oil prices jumped over $2 a barrel on Friday, partly recovering from a mid-week slump, after two missiles fired at US ships in Jordan's Aqaba port fueled concern over the security of supplies from its oil-rich neighbors.

A series of production outages -- and the threat of more to come -- has overshadowed relatively comfortable crude stock levels in the United States, the world's biggest consumer.

Dealers on Monday were keeping watch on Iraq's oil exports of some 1.5 million barrels per day (bpd) that ground to a halt after an earlier power cut.

Global production and refining constraints have kept US oil prices sizzling at an average $53.79 a barrel this year versus an average $41.47 in 2004.

Vulnerability in the crude oil supply chain is leading analysts to speak again of a "fear factor" inflating prices.