Russia's gas producer Gazprom has said it has stopped sending gas to Latvia after accusing it of violating supply conditions as the energy crisis deepens in Europe.
Vladimir Putin has already cut off gas supplies to Poland, Bulgaria, Finland, Netherlands and Denmark, who refused to pay in line with an order by the president requiring rouble accounts to be set up in a Russian bank.
The country has also halted gas sales to Shell Energy Europe in Germany.
In a statement on Saturday, Gazprom did not specify which gas supply conditions Latvia, a European Union and NATO military alliance member bordering Russia, had violated.
Edijs Saicans, deputy state secretary on energy policy at the Latvian Economy Ministry, said Gazprom's move would have little effect given that Latvia has already decided to ban Russian gas imports from January 1, 2023.
"We do not see any major impacts from such a move," he said.
Gazprom's announcement came a day after Latvian energy firm Latvijas Gaze said it was buying gas from Russia and paying in euros rather than the roubles required when trading with Gazprom.
A spokesperson for Latvijas Gaze, however, said on Friday that it was not purchasing gas from Gazprom.
Latvijas Gaze would not name its Russian provider, citing business confidentiality.
EU countries agreed on Tuesday to an emergency regulation to curb their gas use this winter, preparing for a winter of uncertain supplies from Russia.
In March, Putin said the world's largest natural gas producer would require countries designated as "unfriendly" in their stance on Moscow's actions in Ukraine to pay for piped gas in roubles.
The European Commission - which has warned that complying with Putin's order could breach EU sanctions on Moscow - has urged companies to keep paying in the currency agreed in their contracts with Gazprom.
Most are in euros or dollars.
This comes as a senior official in Russian-annexed Crimea accused Ukraine on Sunday of carrying out a drone attack ahead of planned celebrations to mark Navy Day, injuring five and forcing the cancellation of festivities.
The accusation comes hours before Russian President Vladimir Putin is due to oversee Navy Day celebrations in his hometown of St Petersburg and approve Russia's naval doctrine as Moscow presses on with its military intervention in Ukraine.
"An unidentified object flew into the courtyard of the fleet's headquarters," Mikhail Razvozhayev, governor of Sevastopol, home to Russia's Black Sea fleet, wrote on the Telegram messaging app.
"According to preliminary information, it is a drone."
He said Ukraine had decided to "spoil Navy Day for us".