Russia said Tuesday it was expelling 31 diplomats from three European countries in a tit-for-tat move sparked by its military operation in Ukraine.
The Russian foreign ministry declared 15 diplomats from the Netherlands "persona non grata" and gave them two weeks to leave.
Belgium's foreign ministry told AFP the measure targeted 12 diplomats.
Moscow also gave four Austrian diplomats until Sunday to leave, underscoring a break in relations with a country that had been relative neutral since the Cold War.
Belgium called Russia's decision "totally unjustified and unfounded" and regretted a measure that increases "Russia's international diplomatic isolation".
Dutch Foreign Minister Wopke Hoekstra said: "We are now going to see what consequences will arise from the fact that so many colleagues have to leave Moscow and Saint Petersburg."
Moscow's announcement came a week after Austrian Chancellor Karl Nehammer became the first European leader to visit Russian President Vladimir Putin since the Kremlin launched its military operation in Ukraine on February 24.
Russia has still not responded to decisions by Germany and France to each send home 40 of Moscow's envoys, meaning that more expulsions were likely soon.
Moscow on Tuesday also summoned Luxembourg's envoy, warning him that Russia may decide to take reciprocal measures following the tiny European state's expulsion of Moscow's ambassador.
The Russian foreign ministry called a decision by the Netherlands to expel Moscow envoys "groundless" and the step taken by Belgium "provocative".
The ministry said Austria's expulsion of four Russians "seriously damaged both bilateral relations and Austria's international prestige".