Around 8:40 GMT (10.40 in Paris), the Brent North Sea barrel for delivery in June was worth $ 75.23 in London, up 66 cents from the closing on Wednesday, fifteen minutes after reaching $ 75.42.
In New York, a barrel of light sweet crude oil (WTI) for the same date gained 20 cents to 66.09 dollars, minutes after reaching 66.16 dollars.
Prices skyrocketed on Monday after the United States announced the abolition of US exemptions that allowed some countries to import Iranian crude oil despite Washington's sanctions.
"In theory, they have to go between 1 and 1.3 million barrels per day on the market," says Tamas Varga, a PVM analyst, although he thinks "remains to be seen."
Saudi Arabia, the largest exporter in the world, has already pledged to increase its yield to offset Iran's barrels, although Energy Minister Khaled al-Faleh said on Wednesday that the increase would not happen. immediately, according to Bloomberg reports.
On Thursday, WTI's rise was less marked as the US energy news agency reported that crude oil stocks are higher than expected in the United States.
That rose by 5.5 million barrels in the week ending April 19. Any increase in crude oil reserves in the United States is generally interpreted as a sign of lower demand in the largest economy in the world.