The Czech Republic authorities considered the Russian response to Prague's expulsion of 18 Russian diplomats "stronger" than they expected, stressing that his country had requested "solidarity" from European countries.
The Czech Republic's acting foreign minister, Jan Hamacek said: "The reaction is stronger than we had expected, it is more diplomats than the number of intelligence officers we expelled."
Hamacek told a televised news conference that he had asked the foreign ministers of the European Union countries to express solidarity with Czechs.
He added, "I will meet with the prime minister to discuss whether and when the Czech side will need to take further steps."