Russia should pay 'costs' for Czech attack, US says

The attack was "disturbing" and allies needed to send "a firm message that Russia's dangerous actions will be met with an appropriate response", the spokesperson said.

The US also corroborated "the findings of the Czech Republic's thorough and lengthy investigation" into the blast, which concluded that operatives from the Russian military intelligence service, the GRU, caused an explosion at an ammunition warehouse in the town of Vrbětice seven years ago, killing two Czech people.

Nato and the EU issued similar statements the same day.

"Nato allies stand in solidarity over Russia's dangerous pattern of destabilising behaviour", a Nato official told this website.

There was "reasonable suspicion" the GRU did it, the official added, after the Czech Nato ambassador briefed colleagues in Brussels on Tuesday.

And the Czech foreign minister will consult allies again "later this week" on the situation, the Nato official said.

The Vrbětice blast "resulted in the deaths of two Czech citizens, a serious threat to civilian population, and immense material damage," EU foreign service chief Josep Borrell noted.

He backed Prague's decision to recently expel 18 out of 129 Russian diplomats in the Czech Republic over the "criminal activities", while describing Russia's tit-for-tat ejection of almost every Czech diplomat in Moscow as "disproportionate".

"Disruptive actions of Russian intelligence services against the interests and security of the EU and its member states will continue to be met with the staunchest resolve, including at the level of the European Union," Borrell added.

The last time Russia was officially accused of lethal plots on Nato and EU territory was when it tried to assassinate a former Russian spy in Salisbury in the UK using a chemical weapon in 2018.

The US and EU states expelled over 300 Russian diplomats in solidarity with Britain.

The Czech Republic has sent mixed signals on what it wanted from its allies.

Czech prime minister Andrej Babiš downplayed the affair on Monday, saying the GRU attack was a botched operation targeting a Bulgarian arms dealer.

But the Czech foreign ministry urged Borrell to issue a strongly worded statement on Wednesday.

And the Czech foreign minister is expected to ask Nato allies for concrete gestures of support when he speaks with them in the coming days, diplomatic sources said.

"After the attack in Salisbury the alliance showed solidarity in expelling hundreds of Russian diplomats. The Czechs have an equal claim to such solidarity," Jamie Shea, a former senior Nato official, told EUobserver, in a hint of what might happen next.

"It is important the Kremlin knows that it will pay a price for these forms of hybrid warfare," Shea added.

The Russian foreign ministry has called the Czech accusations "unfounded and far-fetched".

But Vrbětice and Salisbury were part of a wider pattern of hostilities, Shea noted.

Russia has, in recent years, also assassinated other people in the UK and Germany and waged cyber attacks on European and US government institutions, as well as on international bodies, such as the Organisation for the Prohibition of Chemical Weapons in The Netherlands and the World Anti-Doping Agency in Canada.

Nato tested

The Czech news comes amid heightened tension after Russia massed troops on Ukraine's border, in what look like preparations for a new invasion in May.

Russian president Vladimir Putin also used belligerent rhetoric in a TV speech on Wednesday, in which he accused the West of plotting a coup in Belarus.

He is under pressure at home, with more than 10,000 people at a protest in Moscow the same day in support of jailed opposition figure Alexei Navalny.

And all that will have to be weighed in the balance when the West decides what to do, Shea told EUobserver.

"Putin seems to be looking for a provocation or casus belli to launch a new aggression against Ukraine, putting, as usual, the blame on Nato," Shea said.

"Given the current military tensions on the Russian-Ukrainian border, the Vrbětice response must be measured and proportionate. Clear messaging is important here ... the allies need to be firm, but to de-escalate the situation," he added.

"This will be the crucial test for Nato and EU diplomacy in the days ahead," he said.