Oil rises back above $71 a barrel

Oil prices are still nowhere near the peak of $147 a barrel last July

Oil prices rose past $71 a barrel on Friday as investors remained optimistic about an economic recovery.

US light crude rose as much as $1.51 to a high of $71.29, before falling back. London Brent gained 2 cents to $69.80.

Oil has risen sharply so far this year and is poised for more as data suggested the worst of the recession may be over, reviving demand for oil.

Oil also gained as a rebel group in Nigeria claimed another attack on a Royal Dutch Shell oilfield.

"There's a lot of focus on the Nigerian situation," said Christopher Bellew, an oil broker at Bache Commodities.

There has been a spate of pipeline bombings and kidnapping of oil workers, with the intensity of the attacks taking oil traders by surprises.

Also, US giant Exxon Mobil said its Baytown refinery suffered an operational glitch that triggered flaring, which could result in lower petrol supplies during the summer season.

Crude oil surged almost 30% last month.