Trading opened at midnight on Monday night. About half an hour later, the futures price of North Sea oil (Brent) had risen 1.6 percent to $89.66 per barrel.
US WTI oil had risen to $84.80, an increase of 1.7 percent.
When trading closed on Friday, Brent oil cost $88.10 per barrel and WTI oil cost $83.40.
Although the tone between the parties has been threatening, no American attacks on Iran have been carried out since the end of July. However, late Sunday evening, reports emerged of attacks on two Iranian mine-launching sites on the island of Larak in the Strait of Hormuz.
The Iranian Revolutionary Guard has promised revenge.
