"There will be a retaliatory response. But overall, of course, this is a very vile and mean provocation by the Czech authorities," Naryshkin told reporters.
On Friday, Czech Prime Minister Andrej Babis announced that two Russian diplomats were declared personae non-gratae in the country.
Babis explained that the decision was connected to claims that a Russian official allegedly brought ricin poison to the country for assassinating officials involved in the dismantlement of a monument to a Soviet marshal in Prague. Moscow has denied the claims.
Rossotrudnichestvo, the Russian foreign cooperation agency, has confirmed that the two expelled diplomats were its employees, and one of them was the acting head of the agency's regional office. The Russian embassy in Prague also called the expulsion a provocation.