Lithuania on Monday said it was expelling Russia's ambassador over Russian aggression in Ukraine, including the "horrific massacre" in the town of Bucha near the capital.
Dozens of bodies were found in mass graves or littering the streets near Kyiv over the weekend. The Kremlin has rejected Western accusations that Russian forces were responsible.
"In response to Russia's military aggression against sovereign Ukraine and the atrocities committed by the Russian armed forces in various occupied Ukrainian cities, including the horrific massacre in Bucha, the Lithuanian government has decided to downgrade the diplomatic representation," Foreign Minister Gabrielius Landsbergis told reporters.
"The ambassador of the Russian Federation will have to leave Lithuania," he said, adding that the Baltic state would also withdraw its ambassador from Moscow.
The move drew an immediate response from Moscow.
"It won't take long for retaliatory measures to follow," Russian foreign ministry spokeswoman Maria Zakharova told AFP.
Landsbergis also said Lithuania will close Moscow's consulate in the port city of Klaipeda, where 20 percent of residents are ethnic Russians.
He described the Bucha killings as a "war crime".
"What the world sees in Bucha, unfortunately, may be only the beginning. As other cities are liberated, we may see more horrific instances of war crimes," he said.
Last month, Lithuania already expelled four Russian diplomats, prompting a tit-for-tat response from Moscow.
