The US and Europe are preparing new sanctions against Russia as tensions escalated in eastern Ukraine.
Pro-Russian rebels paraded European monitors they are holding on Sunday, freeing one but saying they had no plans to release another seven.
June Brent crude was at $109.78 per barrel, up $0.20, by Monday morning after settling down $0.75 on Friday.
US crude for June delivery added $0.32 to $100.92 per barrel, Reuters reported.
On Friday, the contract settled at its lowest level since 7 April, due to pressure from all-time high crude inventories recorded in the week of 18 April.
“If the conflict between the countries escalates, increased fuel demand for military use and heightened risk of disruption will likely continue to strengthen global oil prices,” Barclays analysts said in a note over the weekend.
Russia’s oil pipeline monopoly Transneft said last week it was worried Ukraine may take control of its oil product pipeline to Hungary.
Russia is unlikely to use oil as a political weapon, but investors remained cautious about the risks stemming from the east-west crisis, Newedge Japan commodity sales manager Yusuke Seta told Reuters.
In Libya, the government is assessing damage at the eastern oil port of Zueitina following an eight-month oil blockade.
Zueitina is one of two ports which were due to re-open after the government struck a deal with rebels three weeks ago.
“They are unable to increase exports yet and hence it’s a little bit supportive for Brent,” Seta said.
US crude narrowed the gap with Brent slightly to $8.86 per barrel after it stretched as wide as $9.28 on Friday.
Analysts blamed record crude inventories in the United States for depressing US crude prices despite a rise in refinery utilisation rates.
Crude inventories are unlikely to be drawn down quickly as U.S. gasoline demand remained limited, Seta said said.
“The flow from Cushing to the Gulf coast should stop at some point and that means inventories at Cushing should increase again. This is a bearish factor for West Texas Intermediate,” Seta said.