Russia confirmed Monday that it had expelled a group of Polish and German diplomats in what Moscow called "responsive measures".
"Polish authorities undertook the unfriendly and unfounded move. Due to that, Russia has undertaken adequate responsive measures," Xinhua quoted Russia's foreign ministry as saying in a statement, adding the Polish diplomats had already left Russia.
Neither Moscow, nor Warsaw revealed the number of the diplomats expelled, though some media reports said three Polish military attaches and one employee of the political section had been affected by the decision.
On Friday, Moscow gave the diplomats 48 hours to leave the country.
Earlier this year, Warsaw cancelled a number of joint cultural events with Moscow scheduled for 2015, and in October withdrew accreditation for a Russian journalist working in Warsaw.
On Saturday, Russia also expelled a female German diplomat as a tit-for-tat response to the unspecified "unfriendly actions" of the German authorities against an unnamed Russian official in Bonn.
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Meanwhile, Moscow said the deportation had no link with media reports over the upcoming visit by German Foreign Minister Frank-Walter Steinmeier.
Ties between Russia and major European countries have been strained over the unsettled Ukraine crisis, with Moscow repeatedly denying to have been playing destabilising role in the conflict.