Crude oil prices have hit fresh highs as fears grow over the extent of damage done by Hurricane Katrina to oil output in the Gulf of Mexico.
Gas prices hit all-time highs in the US after Katrina struck
A barrel of US light crude was trading more than $3 higher at $70.85 early on Tuesday afternoon, surpassing Monday's previous all-time high of $70.80.
Katrina has shut down 90% of the Gulf's oil output and several refineries, stoking fears about future oil supply.
Several Opec members have called for its production limits to be raised.
Brent crude also soared on Tuesday, gaining $3.37 to $68.24.
However, in late trading US light crude fell back on profit-taking to just under $70 a barrel, ending at $69.81 on Tuesday.
The US Department of Energy said at least nine Gulf Coast refineries were shut as a result of the storm, with another four reducing production rates.
"This is an extremely serious situation," Tom Kloza, director of oil consultants, the Oil Price Information Service, said.
While Katrina has lost some of its power, estimates are that total damages may be as much as $25bn (£14bn).
The market is increasingly worried that Katrina has done long-lasting damage to refining and extraction operations in the Gulf of Mexico, putting further pressure on global oil supplies.
Shell said one of its off-shore platforms had been damaged while two of its drilling rigs are adrift in the Gulf of Mexico.
Hundreds of other platforms have been closed, reducing output by 1.4 million barrels, equivalent to 7% of US domestic demand.
The closure of up to eight refineries and the partial shutdown of a further two has put additional strain on the country's already stretched refining capacity.
Fears about the availability of gasoline forced wholesale prices to a record $2.85 a gallon on the Gulf Coast.
The clean up after Katrina may take months and cost billions of dollars
Analysts have warned that should a serious disruption occur, the cost of a barrel of crude could break the $100 barrier.
That could have a negative impact on consumer spending and global growth.
"The primary uncertainty right now is the extent of damage and headlines there will go straight into prices," said Deborah White, senior energy analyst at SG Commodities.
"Peak hurricane season isn't until mid-September through mid-October and we have had two hurricanes hit the Gulf Coast already."
Several of the refineries which closed operations are up and running again.
Analysts said that getting refining capacity back on line was the key to minimising the problems caused by Katrina.
Oil companies are rushing teams to the Gulf Coast to assess damage, with fears that off-shore production and natural gas might also be severely hit.
The US government is considering releasing some of its strategic petroleum reserve to help bring prices down.
Opec - the Organization of the Petroleum Exporting Countries - is considering raising its production ceiling at a meeting next month, although analysts have said this would be a mainly symbolic gesture.
The group, which consists of countries including Saudi Arabia, Iraq, Nigeria and Venezuela, is already busting its limits for daily crude production and has little spare capacity.
Nigeria's top oil official, Edmund Daukoru, has called for an increase of one million barrels a day, while Saudi Arabia has voiced support for a smaller 500,000 rise.
In a sign of how seriously Opec members view the crisis, the United Arab Emirates increased its own petrol prices by 30%.
The UAE, which includes the Persian Gulf state of Abu Dhabi, pumps 2.5m barrels per day.
Nevertheless petrol prices are going up to between $1.71 to $1.83 per gallon, after local petrol retailers complained that they were facing heavy losses.