Gazprom is bumping up the amount Ukraine pays for gas by a third today.
The Russian state energy firm is removing the discount for its smaller neighbour because it has not paid for gas Gazprom supplied last year.
The price is going up by $100 per 1,000 cubic meters, according to reports.
Gazprom CEO Alexei Miller is quoted as saying: “In line with the current contract on delivering gas, the price for Ukraine in the second quarter [of 2014] will be $385.50.”
At the start of March, Mr Miller met Russian Prime Minister Dmitry Medvedev to discuss Ukraine’s unpaid gas bill, when they agreed to scrap the gas discount previously given to Ukraine by Russian President Vladimir Putin.