The Czech government on Thursday ordered Russia to remove most of its diplomatic staff from Prague.

The announcement marks an escalation in a diplomatic row over the alleged role of Russian spies in a deadly blast at a Czech munitions depot in 2014. It is the worst dispute between the two countries in decades.

Czech Foreign Minister Jakub Kulhanek said Moscow would have until the end of May to withdraw 63 embassy employees, a move he said aimed to bring staff numbers in line with those at the Czech Embassy in Russia.

"We will put a ceiling on the number of diplomats at the Russian Embassy in Prague at the current level of our embassy in Moscow," Kulhanek said. "I do not want to needlessly escalate ... but the Czech Republic is a self-confident country and will act as such. This is not aimed against Russians or the Russian nation, but a reaction to activities of Russian secret services on our territory."

According to figures from the Czech Foreign Ministry, there are currently 32 staff at the Czech Embassy in Russia compared to 95 at the Russian Embassy.

The Czech counterintelligence service has repeatedly warned that the Russian Embassy — by far the biggest foreign mission in Prague — was being used as a base for undercover spies.

What is behind the diplomatic row?

The dispute erupted on Saturday when Czech authorities expelled 18 Russian diplomats, accusing them of being secret agents with ties to the 2014 explosion that killed two people. They also alleged that two Russian spies wanted over the 2018 poisoning of former Russian double agent Sergei Skripal in England were involved in the blast. 

Moscow denied the allegations and responded in kind by expelling 20 Czech diplomatic staff. Prague said the loss of those employees had effectively paralyzed operations at the embassy.

"Russia's reaction was absolutely disproportionate, the diplomats didn't do anything wrong," Kulhanek said.

Moscow vows response

Russian Foreign Ministry spokeswoman Maria Zakharova on Thursday said that Moscow would respond swiftly to Prague's decision to cap diplomatic staff.

"At the moment Prague is on the path to destroying relations," she said at her weekly briefing. "They have gotten stuck in unbridled Russophobia.''

Zakharova said that the Foreign Ministry had called in the Czech ambassador to denounce an "escalation of an anti-Russian campaign."

Slovakia expels Russian envoys

Both NATO and the EU have backed the Czech Republic in the dispute.

Slovakia, which formed a single country with the Czech Republic until 1993, said Thursday it would expel three Russian diplomats in solidarity with Prague. It said the move was also in response to information from its intelligence services about Russian activities.

Zakharova said Moscow was "deeply disappointed by the unfriendly actions of Bratislava."

nm/msh (AFP, Reuters, AP)