Two Russian men suspected of carrying out the 2018 Salisbury poisonings are being linked to an explosion at an arms depot in the Czech Republic.
Evidence links the 2014 explosion, and an attempted poisoning in Bulgaria, to a unit of Russian military intelligence – the GRU – the BBC has learnt.
European intelligence agencies believe the GRU’s Unit 29155 is tasked with sabotage, subversion and assassination.
A senior Russian parliamentarian has called the claim absurd.
Czech authorities say they are expelling 18 Russian diplomats believed to be intelligence operatives in retaliation for the explosion, which killed two people.
Czech Prime Minister Andrej Babis said the country had to react to revelations tying the blast to the GRU.
The country will inform Nato and European Union allies about its suspicions, and will discuss the matter at an EU foreign ministers’ meeting on Monday, its acting Foreign Minister Jan Hamacek said.
A huge explosion tore apart an ammunitions storage depot in a forest in the Czech Republic on 16 October 2014.