The natural gas spigot could be closed for Ukraine as early as Tuesday unless it pays for more deliveries in advance, Russia's energy minister said Friday.

Russian energy company Gazprom confirmed it received $15 million from its Ukrainian counterpart, Naftogaz, which ensures gas deliveries until Tuesday.

"They can also pay for Tuesday - it depends on them now," Energy Minister Alexander Novak said. "If they want gas, they have to pay."

Gazprom in the winters of 2006, 2009 and 2014 cut gas deliveries through Ukraine briefly in response to contractual disputes with Kiev. That left downstream consumers in Europe short on natural gas supplies.

The latest payment row coincides with ongoing skirmishes between pro-Russian rebels in eastern Ukraine and government forces, though a mid-February cease-fire agreement is slowly taking hold in the region.

U.S. Secretary of State John Kerry meets next week with Russian Foreign Minister Sergei Lavrov to discuss the crises.

Tuesday coincides with planned trilateral meetings with Ukrainian and European officials to discuss ongoing gas transit issues.

"I have confirmed my participation and we plan to discuss in Brussels a whole range of our mutual relations," Novak said.

The European market gets about a quarter of its gas needs met by Russia, though most of that gas runs through the Soviet-era pipeline network in Ukraine. Ongoing transit issues have sparked diversification efforts on both sides.

Novak said Friday gas supplies to Eastern economies should increase nearly tenfold by 2035. A so-called Power of Siberia natural gas pipeline will ensure Russian gas deliveries to China and the minister said at least three related agreements will be signed this year.