Janez Jansa, who currently holds the EU’s rotating presidency, posted a tweet on Thursday which showed a number of current and past MEPs connected to Hungarian philanthropist George Soros.
The picture, showing Soros at the centre and the other figures circling him, was headed: “13 of the 226 known Soros puppets in the EU Parliament.”
The tweet sparked the immediate fury of EU Parliament President David Sassoli.
The Italian politician tweeted: “We urgently call on Janez Jansa to cease the provocations against members of the European Parliament.
“Attacks on members of this house, are also attacks on European citizens.
“A constructive collaboration with the rotating Council Presidency can only be based on mutual trust and respect.”
French minister for European Affairs Clement Beaune also criticised the Slovenian Prime Minister.
He said: “Dubious attacks on MEPs have no place in our democratic life. We need respectful debate, not provocations.”
Mark Rutte, Dutch Prime Minister, went even further as he summoned the Slovenian ambassador over the offensive tweet.
He said: “Tasteless tweet by Janez Janša about MEPs.
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He said: “Prime Minister Janez Janša, this is a despicable, antisemitic trope and an insult to hardworking democrats.
“On behalf of the RenewEurope family, I demand you to retract and apologize! There is no place for these vile slurs in European politics.”
Despite deleting the original tweet, the Slovenian leader did not appear to backtrack on his claims.
In a tweet, he replied to Mr Rutte: “Well, Mark, don’t waste time with ambassadors and media freedom in Slovenia.
“Together with Sophie in’ t Veld [Dutch MEP], protect your journalists from being killed on the streets.”
This morning, he justified his accusation by tweeting a list published by the Soros foundation on “reliable allies in the European Parliament between 2014 and 2019”.
He claimed: “In discussing the supporters of billionaire George Soros in the European Parliament there is no conspiracy theory, as the making of the list was commissioned and published by the Soros Foundation Open Society alone.”
The picture tweeted by Mr Jansa saw a red arrow pointing to Ms in ‘t Veld.
The Dutch MEP is leading an eight MEP delegation visiting Ljubljana from Wednesday to Friday to look into Slovenia’s situation concerning rule of law, media freedom and the fight against corruption.
By referring to “Soros puppets”, the Slovenian premier was perpetrating a common far-right conspiracy theory which claims the Jewish billionaire secretly controls the world’s politics and economics.
The Slovenian Government was contacted by Express.co.uk for comment.