Russia’s Gazprom has halted natural-gas exports to neighboring Finland, Finnish state-owned energy company Gasum said, the latest escalation of an energy payments dispute with Western countries.

Gazprom Export has demanded that European countries pay for Russian gas supplies in rubles because of sanctions imposed over Moscow’s unprovoked invasion of Ukraine, but Finland has refused to do so.

“Gas imports through Imatra entry point have been stopped,” Gasgrid Finland said in a statement.

Imatra is the entry point for Russian gas into Finland.

Gasum added that gas would instead be supplied from other sources through the Balticconnector pipeline, which connects Finland to Estonia.

The move follows Finland’s decision earlier this week to apply to join NATO as it seeks to bolster its security in light of Russia’s aggression against Ukraine.

Moscow has already cut off gas to other countries, including Bulgaria and Poland, after they refused to comply with the new payment terms.

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

Finland also agreed on May 20 to charter a storage and regasification vessel from a U.S company to help replace Russian supplies. The vessel turns supercooled liquefied natural gas back into gas.