Russia's state-owned gas company Gazprom said it had cut supplies to Latvia on Saturday, citing a breach of contract.
The company did not specify which terms Latvia had violated in a statement issued on Saturday.
"Today, Gazprom stopped its gas supplies to Latvia specified in the July request due to a violation of the conditions established for gas withdrawal," the company wrote in a statement published on social media.
The announcement comes several days after "Latvijas gaze" (Latvian gas) said it is now buying gas from Russia, but not from Gazprom, Latvia's public broadcaster LSM reported. Gazprom holds a 34 percent stake in the company.
Latvijas gaze head Aigars Kalvitis refused to reveal the name of the new Russian supplier on the basis that "it is commercial information that we do not discuss in the public space."
Russia has already cut off gas supplies to Poland, Bulgaria, Finland, the Netherlands and Denmark.
All three Baltic states stopped importing Russian gas on April 1, but Latvia resumed buying gas again at the end of April.
The Latvian government has agreed it would stop buying Russian gas completely from January 2023 but it can still fill the Incukalns underground gas storage facility until August 31.
Editor: Helen Wright