Russia's foreign ministry summoned the Polish ambassador on Friday following Warsaw's expulsion of Russian diplomatic staff, RIA news agency reported.
Warsaw expelled three Russian diplomats earlier this month, saying that they were involved in "activities to the detriment" of Poland, and Russia replied last week by saying it would expel five Poles.
(Reporting by Anton Kolodyazhnyy; Writing by Gabrielle Tétrault-Farber; Editing by Mark Trevelyan)
