The Czech Republic has demanded compensation from Russia over a deadly 2014 explosion at an ammunition depot.
Prague has accused Moscow of involvement in the blast at Vrebtice, which killed two people.
In April, the Czech Prime Minister said they had "irrefutable evidence" that two Russian GRU agents were behind the depot explosion. Russia has denied any involvement.
On Monday the Czech Foreign Ministry announced that had summoned Russia’s ambassador to Prague to request full compensation for damages caused by the explosion.
"The Czech Republic has invoked international responsibility of Russia for Vrbětice," a statement read.
The ministry said deputy Foreign Minister Martin Smolek handed Ambassador Aleksandr Zmeyevsky a diplomatic note, requesting "full reparation for the injury caused by this internationally wrongful act".
Prague also said they had invited Russia to enter into negotiations on this matter.
The allegations have resulted in a serious diplomatic crisis between the Czech Republic and Russia, with dozens of diplomats ordered to leave their respective embassies.
Moscow has listed the Czech Republic as an "unfriendly state" that has "carried out unfriendly actions" against Russia.
But Smolek told Zmeyevsky that the Czech Republic's inclusion on the list was a violation of international law and called on Moscow to cancel the measure.
The same two Russians named by the Czech Republic in their investigation into Vrebitce are also suspected by British authorities of poisoning former Russian double agent Sergei Skripal and his daughter in Salisbury in 2018.