The Russian currency has fallen by more than 3 percent after escalated fighting in eastern Ukraine over the weekend.

The ruble tumbled to 65.8 to the dollar early Monday from 63.7 on opening, after Western leaders announced that they were considering further punitive measures against Russia for what they say is its role in supporting the separatists in eastern Ukraine. Russian officials blamed Ukrainian forces for an attack that left 30 dead in the city of Mariupol.

At least 4,700 people have been killed in east Ukraine since fighting began in April, but fighting this week was the most intense since a cease-fire deal was signed in September.

The Russian currency, buffeted by Western sanctions and plummeting oil prices, has already lost about half its value in the past year.