An attack by suspected Muslim militants on a US consulate in Saudi Arabia, Opec's leading producer, and the occupation in Nigeria by villagers of three oil-producing platforms in a row over jobs also supported prices.

US light crude by 1200 GMT was trading 38 cents higher at $42.93 a barrel, climbing away from Friday's $42.05 trough. Prices fell $7 last week and are down from a late-October peak of $55.67 a barrel.

London Brent crude rose 30 cents to $39.66 a barrel.

In Saudi Arabia gunmen attacked the US consulate in the western Red Sea city of Jeddah.

It was the first major attack since the killings in May by militants loyal to Saudi-born al Qaeda leader Osama bin Laden of Westerners in the eastern oil city of Khobar.

Last week's price fall raised the alarm among some members of the Organization of the Petroleum Exporting Countries which meets on Friday in Cairo.

For the first time in six months, Opec is talking of the need to clamp down on quota-busting production, curbing its highest output in 25 years, and may consider cutting formal supply limits.

"There's been a change in sentiment on the possibility Opec could cut output, but of course if prices go up on that expectation it may make it more difficult for them to do so," said Christopher Bellew of brokers Bache Financial.

"While Opec is undoubtedly relieved that prices have cooled, the speed of the past few days' correction should worry them," said Societe Generale in a report. "If unchecked, market momentum risks taking prices from correction to collapse."