The price of crude oil has retreated slightly after hitting record highs above $142 a barrel, amid concerns that supply will not meet demand.
In London, Brent crude was trading at $140.16, having earlier hit $142.13.
Producers' group Opec has been under pressure to boost production, though recent reports have shown its members are split over whether to lift output.
Libya has threatened to cut production because the market is well supplied.
Libya's most senior oil official, Shokri Ghanem, said on Thursday he was looking into the possibility of cutting production in response to US threats against oil producers.
Analysts blame the price of crude on a variety of factors from basic supply and demand to hedge funds.
"We believe the factors driving oil prices higher are fundamental and not speculative," Deutsche Bank said in a research note.
"Oil needs to rise to $150 a barrel for oil as a share of global Goss Domestic Produce to reach the levels that occurred in the early 1980s," according to the bank.
The US House of Representatives has passed a bill that would allow the Justice Department to sue Opec members for limiting supplies.
But the bill has yet to be backed by the Senate and the White House has already said it would veto the bill.
