Brent and U.S. West Texas Intermediate (WTI) crude futures were both up 0.4% on Monday, paring some gains after rising as much as 1.3% in early Asian trade. Brent was trading 27 cents higher at $74.12 a barrel at 0234 GMT, while WTI was up 28 cents at $69.44 a barrel, Reuters reported.

A clash between Moscow and Russian mercenary group Wagner was averted on Saturday after the heavily armed mercenaries withdrew from the southern Russian city of Rostov under a deal that halted their rapid advance on the capital.

However, the challenge has raised concerns about possible disruption of Russian oil supply.

Consultancy Rystad Energy said in a note late on Sunday it did not expect to see a significant increase in oil prices due to the "short-lived event."

"We do, however, believe that the geopolitical risk amid internal instability in Russia has increased," Rystad said.

RBC Capital Markets analyst Helima Croft said there were concerns that Russia would declare martial law, preventing workers from showing up to major loading ports and energy facilities, potentially halting millions of barrels of exports.