Oil prices rose as the Russia's invasion of Ukraine escalated, causing a Ukrainian nuclear power plant, Europe's largest, to catch fire after an attack from Russian troops.
U.S. benchmark crude was up $1.34 to $109.10 per barrel in electronic trading on the New York Mercantile Exchange. It lost $2.93 to $107.67 per barrel on Thursday.
Brent crude, the international price standard, added 86 cents to $111.32.
Russia is a key oil producer and prices have been rising as global supplies are threatened by the conflict, raising concerns that persistent inflation could become even hotter.
Trading activity for Russian crude oil appears frozen as buyers are hesitant in making purchases because of the sanctions, according to Reuters.
Prices ended in Thursday's trading session as investors focused on the revival of the Iran nuclear deal, which would boost Iranian oil exports and ease tight global supplies.
Oil prices are set to post their strongest weekly gains since the middle of 2020, with U.S. crude up more than 22% and Brent at 16% after hitting their highest in a decade this week.