Russia’s Gazprom says Ukraine has paid $1.45 (1.16 billion euros) towards its outstanding gas bill.
That is the first step towards Russia resuming supplies to Ukraine, which were cut off in June.
It is the first payment by Ukrainian energy firm Naftogaz since May, when a row over gas pricing and unpaid debts escalated between Moscow and Kyiv.
Talks between Russia and Ukraine – brokered by the European Commission – resulted in a temporary agreement on a gas price, a debt repayment schedule and a resumption of gas supplies until the end of March.
It is expected flows will start again by the end of this week.
Russia has said the debt stands at either around $4.5 billion (3.6 billion euros) or over $5 billion (4 billion euros), depending on the pricing for gas Kiev received between April and June.
Ukraine used to get half of the gas it needs from Russia and 50 percent of the gas the European Union uses also passes through