Oil prices extended gains for a third session on Monday, with Brent rising above $80 a barrel to its highest in more than four months, as wider U.S. sanctions are expected to affect Russian crude exports to top buyers China and India.

Russia's Foreign Ministry on Saturday denounced new U.S. sanctions against Moscow's energy sector as an attempt to harm Russia's economy at the risk of destabilising global markets and said the country would press on with large oil and gas projects.

The White House has announced new sanctions against Russian oil companies, which are expected to cost Russia billions of dollars per month. The restrictions target Gazprom Neft and Surgutneftegas, as well as 183 ships involved in oil exports.

Chinese and Indian refiners will source more oil from the Middle East, Africa and the Americas, boosting prices and freight costs.

The new US sanctions on Russia's energy sector will significantly reduce its income. John Kirby, the coordinator for strategic communications at the National Security Council states, they will also force Moscow to make a "tough choice,

The White House has announced new sanctions against Russian oil companies, aimed at inflicting losses on Russia amounting to billions of dollars each month. The restrictions target Gazprom Neft and Surgutneftegaz,