Oil prices hit $75 on April 24, the highest level in nearly three and a half years, as fears mounted over the prospect of new US sanctions on Iran.
Brent crude jumped for the sixth consecutive day, trading as high as $75.27 before falling back slightly.
By May 12, the US will decide whether to abandon a nuclear deal with Iran and re-impose sanctions.
Such a move on the third-biggest oil producer in the OPEC cartel threatens to further tighten global supplies.
Oil prices have been rising since the OPEC nations, as well as other producers including Russia, decided to restrict output last year.
Last November they agreed to extend those cuts until the end of 2018.
President Donald Trump has said that unless European allies fix what he has called “terrible flaws” in the accord by May 12, he will restore US economic sanctions on Iran.
The other nations that signed the deal – France, Germany, the UK, Russia and China – all want to keep in place the agreement, which has halted Iran’s nuclear program in return for most international sanctions being lifted.