MOSCOW, Russia: In the latest escalation of an energy payment dispute with Western nations, Russia's Gazprom has halted gas exports to neighboring Finland.

Due to sanctions imposed on Moscow over its invasion of Ukraine, Gazprom has demanded that European countries pay for Russian gas deliveries in roubles, but Finland has refused to do so.

Finland is also applying to join the NATO military alliance, a decision driven by Russia's invasion of Ukraine.

In a statement this week, Finnish gas system operator Gasgrid Finland said, "Gas imports through Imatra entry point have been stopped."

Also, Finnish state-owned gas wholesaler Gasum said Gazprom had warned that flows would be halted from 0400 GMT on May 21.

"Natural gas supplies to Finland under Gasum's supply contract have been cut off. Starting from today, during the upcoming summer season, Gasum will supply natural gas to its customers from other sources through the Baltic connector pipeline," Gasum said in a statement.

While most gas used in Finland comes from Russia, gas only accounts for about 5 percent of its annual energy consumption.

Moscow cut off gas supplies to Bulgaria and Poland last month after they refused to comply with the new rouble payment terms. Most European supply contracts are denominated in euros or dollars, rather than roubles.

Gasum, the Finnish government and individual gas consuming companies in Finland have said they were prepared for a shutdown and will manage without Russian gas.

"The Finnish gas system is in balance, both physically and commercially," Gasgrid added.

Meanwhile, Finland said it will charter, starting in the fourth quarter this year, a storage and regasification vessel from Excelerate Energy in the U.S. to help replace Russian supplies.