Crude oil prices fell Monday as traders weighed possibly higher Russian supplies hitting the market after U.S. sanctions relief on Friday.
Brent crude futures, the international benchmark, fell 1.80% to $107.88 per barrel. U.S. West Texas intermediate lost 1.14% to $100.25 per barrel.
Ukraine bombing of oil facilities in Russia and more tankers coming under attack in the Persian Gulf, however, have clouded the supply outlook.
Fires broke out at an oil terminal and depot in St. Petersburg after Ukraine launched a massive wave of drone strikes on Sunday, St. Petersburg Governor Alexander Beglov said in a post on Telegram.
The terminal in St. Petersburg exports about 120,000 barrels per day of refined products, mostly fuel oil, according to data from Kpler. It is unclear how bad the damage is at the facility.
Ukraine briefly paused strikes on Russian energy facilities after U.S. President Donald Trump declared on Oct. 11 that Kyiv and Moscow had agreed to a truce.
In the Middle East, meanwhile, two tankers were attacked off the coast of Saudi Arabia in the Persian Gulf on Friday, according to incident reports from the United Kingdom Maritime Trade Operations Centre.
A small boat fired a rocket-propelled grenade at an unidentified tanker 78 nautical miles northeast of Al Jubayl, according to UKMTO. Another tanker, the ST3, was hit by an unknown projectile, UKMTO reported.
Iran has escalated attacks on tankers in the Persian Gulf, Strait of Hormuz and Gulf of Oman in an effort to choke off crude oil exports from the region.