It then pared gains, as the vital Strait of Hormuz remains open to tankers.
US strikes on Iran over the weekend have added to risks for global oil supply, which has so far been unaffected by some of the most extreme military actions in the Middle East in years.
Brent crude jumped early on Monday to trade above US$80 ($103.16) a barrel for the first time since mid-January after US President Donald Trump said air attacks had “obliterated” Iran’s three main nuclear sites.
