World oil prices set new all-time highs before retreating as a Russian court threw another financial lifeline to troubled oil giant Yukos.

New York's light, sweet crude for delivery September bolted to a record 44.77 dollars before closing at 43.95 dollars, down 46 cents.

Brent North Sea crude oil for September shot to a record 41.50 dollars, then closed at 40.63 dollars, down 49 cents.

Prices were roiled by the doomed-again, saved-again saga of Russian oil titan Yukos.

A Moscow court ruled that Russian justice ministry bailiffs had no right to freeze the assets of Yuganskneftegaz, Yukos's largest oil producing subsidiary, accounting for around 60 percent of its output.

Mid-week, bailiffs had thrown the oil titan a lifeline by allowing it access to bank accounts to carry on operating as it struggles to repay a massive tax bill.

The following day, the bailiffs reversed the decision, sending the world energy markets in a spin.

"People don't know how to react to the Yukos court decisions going back and forth in the last couple of days," said Wachovia analyst Jason Schenker.

The slide in prices Friday was not too severe, however, he said.

"I think next week we'll reach more highs."

Yukos' assets were frozen last month and the company was to be sold as bailiffs tried to recover 3.4 billion dollars in back taxes.

Traders reacted with some confusion to the latest twist.

"The Yukos situation is not very clear," said Prudential Bache broker Tony Machacek in London.

Prices had been lifted earlier in the day by news of a fire late Thursday at a BP gasoline refinery in Houston, Texas. But BP said Friday the refinery unit was undamaged by the fire and had resumed operations.

"I think the market briefly went higher when that news first came out but then when it was known that production was at near-capacity we sort of slipped back off again," said Machacek.

New York's contract could test 45 dollars a barrel within days and even breach 50 dollars during the US and European winter, some analysts said.

"We're expecting prices to come off in the third quarter, but there remains a possibility that this winter, if we have a supply loss or if simply demand doesn't slow down, then at some times you could see (the New York contract) test 50 (dollars)," said Societe Generale economist Deborah White.

Traders largely shrugged at OPEC's latest assurances that it was

on standby to increase oil supplies by up to 1.5 million barrels per day (bpd) to help to cool prices.

"We are ready to increase production between 1.0-1.5 million barrels per day and this issue will be discussed in the September 14 meeting in Vienna, " OPEC president Purnomo Yusgiantoro told reporters in Jakarta.

High oil prices, combined with a weaker-than-expected US jobs report for July, also depressed world stock markets.

In New York, the Dow Jones industrials average of 30 top stocks plunged 147.70 points, or 1.48 percent, to finish at at 9,815.33, the lowest since November 2003.

In Europe, London' FTSE 100 index fell 1.71 percent to 4,337.9 points, Frankfurt's DAX 30 slid 2.65 percent to 3,727.74, while in Paris the CAC 40 was 2.60 percent lower at 3,528.64.

In Asia, the Tokyo Stock Exchange's benchmark Nikkei-225 index lost 0.80 percent to 10,972.57 points while Hong Kong's Hang Seng Index fell 0.11 percent to 12,478.68.