Crude oil prices rose today as supply was tightened by attacks on Iraqi pipelines and threatened by a possible halt to output from Russia's top oil producer.
With US oil markets closed for Independence Day, crude futures in Europe and Asia also took support from uncertainty about whether or not Opec would carry out a planned production increase of 500,000 barrels per day (bpd) from August.
Mr Tony Nunan, manager of Mitsubishi's petroleum trading business in Tokyo
Brent crude on London's International Petroleum Exchange was up 73 cents to $36.65 a barrel, erasing Friday's 15-cent loss.
"There's an underlying fear that Iraq pipelines will blow up and exports will halt," Tony Nunan, manager of Mitsubishi's petroleum trading business in Tokyo said, adding that the market saw much upside potential on fears of a supply shortage.
Iraq used to export around two million bpd of crude - all through the south - before the latest attacks.
Traders said that supply from Russia, the world's second-largest oil exporter after Saudi Arabia, remained under threat even after the Yukos corporation said police had not seized vital equipment that helped keep its vast oilfields running.
This was a small comfort ahead of a week that could see the bankrupting of the producer of one-fifth of Russia's supply. Yukos must settle a $3.4 billion bill for back taxes by Wednesday evening.