Opec, the oil producing cartel, has warned that the price of crude could keep rising to reach $200 a barrel.
Opec president Chakib Khelil blamed the falling value of the US dollar, which makes other assets, including oil, more attractive for foreign investors.
His comments came as oil prices hit a fresh high, just below $120 a barrel.
Prices were lifted by a strike at a UK refinery that disrupted North Sea production, and supply problems in Nigeria due to pipeline attacks.
BP shut down a key North Sea pipeline at the weekend after staff walked out of the Grangemouth refinery in Scotland in a two-day strike over pensions.
Providing a third of UK oil output, the closure of the Forties pipeline has raised fears about supply shortages.
US light crude hit a high of $119.93 a barrel before edging down to finish at $118.79.
In doing so, it passed the previous record mark of $119.90 a barrel achieved on Friday.
In London, Brent crude ended at $116.74 a barrel after earlier rising to a peak of $117.51 a barrel on Monday
