Russia's Foreign Affairs Ministry said on Sunday it would take tough retaliatory measures against the Czech Republic over Prague's expulsion of 18 Russian diplomats on what Moscow said were unfounded and absurd grounds.
The Czech Republic expelled 18 Russian embassy staff on Saturday over the suspected involvement of Russia's intelligence services in a 2014 ammunition depot explosion that killed two people.
"We will take retaliatory measures that will force the authors of this provocation to fully understand their responsibility for destroying the foundation of normal ties between our countries," the ministry said in a statement.