PRAGUE — Russia’s unraveling relations with the West took a dramatic turn for the worse on Thursday when the Czech Republic, furious over what it said were Moscow’s fingerprints on a military-style sabotage attack on a Czech weapons warehouse in 2014, ordered the expulsion of as many as 60 Russian diplomats.
The Czech move, announced a day after President Vladimir V. Putin of Russia warned that the West risked a “fast and tough” response if it interfered with his country, escalated not only a diplomatic crisis between Prague and Moscow but a wider showdown between Russia and NATO, of which the Czech Republic is a member.
With Russian troops massing near the border with Ukraine and President Biden taking a tough stand against the Kremlin, Mr. Putin on Wednesday bluntly warned the West not to test Russia’s resolve in defending its interests, telling it not to cross unspecified “red lines” that he said would be defined by Russia.
The slashing of staff at Moscow’s embassy in Prague does not directly challenge Russian security. But it will severely damage intelligence operations, something that Mr. Putin, a K.G.B. officer in Eastern Europe during the Cold War, views as vitally important.
ordered out 20 Czech diplomats. Russia, which has used its Prague embassy as a center of espionage across the region, according to intelligence experts, previously had far more diplomats in the city than the Czech Republic had in Moscow.
Sergei V. Skripal, in the English town of Salisbury.
Two Russians identified by Britain as the main culprits in the Salisbury attack, both members of a military intelligence sabotage and assassination squad known as Unit 29155, turned out to be the same men Czech investigators had long suspected of involvement in the ammunition warehouse blasts but had not been able to identify.
Both men arrived in the Czech Republic under false names several days before the blasts and traveled to the site of the warehouse in Vrbetice, leaving on the day of the first explosion on Oct. 16, 2014.