Russia says it has expelled several Polish diplomats in response to Poland's recent expulsion of Russians suspected of espionage.

The tit-for-tat moves come as Poland and the Czech Republic say they have detected intensified efforts by Moscow's intelligence services to extend their influence in their countries.

Russian's Foreign Ministry said Monday that Polish authorities took the "unfriendly and unwarranted step" of expelling some of its diplomats.

It added that "in connection with this, the Russian side has undertaken adequate response measures, and a number of Polish diplomats have already left our country because of activities incompatible with their status," diplomatic jargon for spying.

A reporter for Polish broadcaster TVN, Andrzej Zaucha, reported from Moscow that four Polish diplomats were told Friday afternoon that they had 48 hours to leave Russia.