Russia said on Monday it was downgrading diplomatic relations with NATO member Estonia, accusing it of "total Russophobia", and Tallinn responded by telling Moscow's envoy to the Baltic nation to leave.
Estonia and its Baltic neighbours Latvia and Lithuania have been among a group of NATO allies arguing strongly for Germany to provide its Leopard battle tanks to boost Ukraine in fighting off Russia's invasion.
The Russian Foreign Ministry said it had told the Estonian envoy he must leave next month, and both countries would be represented in each other's capitals by an interim charge d'affaires instead of an ambassador.
Estonia responded in kind, telling the Russian envoy to leave by Feb 7, Foreign Affairs Minister Urmas Reinsalu said.
"We will continue to support Ukraine as Russia is planning large-scale attacks, and we call on other like-minded countries to increase their assistance to Ukraine," Reinsalu said in a statement.
Estonia joined some other Western countries last week in sending more weapons of its own to Ukraine, reports Reuters.
Moscow said Monday's move was in response to an Estonian decision to reduce the size of the Russian embassy in Tallinn.
"In recent years, the Estonian leadership has purposefully destroyed the entire range of relations with Russia. Total Russophobia, the cultivation of hostility towards our country have been elevated by Tallinn to the rank of state policy," it said.
Commenting on the downgrading of ties, Russian Foreign Ministry spokeswoman Maria Zakharova said: "The Estonian regime has got what it deserved."
Estonia told Russia on Jan 11 to reduce the number of diplomats at its embassy in Tallinn to eight, equivalent to the number of Estonian diplomats in Moscow.
Last April, Lithuania threw out its Russian envoy and downgraded diplomatic representation to the level of charge d'affaires, after Ukraine accused Russian forces of killing civilians in the town of Bucha.