Hungary did the same before because of the Skripal-affair, the poisoning of a former double agent in the UK. According to 24.hu, the Russian foreign ministry summoned the Hungarian ambassador, János Balla and gave him a protest list.
Tit for tat: a Hungarian for a Russian
According to the document, it is a tit-for-tat move responding to Budapest’s “unfriendly and unreasonable move” to pronounce persona non grata one of the workers of the Russian Embassy of Budapest because of the unproven claims of Great-Britain regarding the Skripal-affair. Hungary – in spite of its warm ties with Russia – expelled the Russian diplomat
because of the solidarity between allies,
in this case with Great-Britain.
Because of the poisoning of Sergei Skripal, Western countries expelled Russian diplomats one after the other. Moreover, NATO did the same. As a result,
the number of expelled diplomats has reached 120.
In fact, the British delegation to the Organization for the Prohibition of Chemical Weapons (OPCW) rejected a Russian proposition for a joint investigation regarding the poisoning of former double agent Sergei Skripal and his daughter.
Furtermore, the delegation even called the proposition “pervert”. OPCW discusses the issue behind closed doors in Hague. In fact, it was Russia that suggested the session to be called together. According to President Putin, they planned to discuss twenty questions. British professionals claim that Skripal and his daughter were killed by the Novichok nerve agent which was developed by the Soviet Union.