(Bloomberg) -- Italian Interior Minister Matteo Salvini and Jean Asselborn, Luxembourg’s minister for foreign affairs, are locked in a bitter war of words about European migration.

The feud started at a Vienna conference on Friday. Salvini posted a video on his Facebook page of an exchange with Asselborn, who interrupted the Italian’s speech with a profanity after Salvini likened African immigrants to slaves.

“I’m paid by citizens to help our young people start having children again the way they did a few years ago, and not to uproot the best of the African youth to replace Europeans who are not having children anymore,” Salvini said. “Maybe in Luxembourg there’s this need, in Italy there’s the need to help our kids have kids, not to have new slaves to replace the children we’re not having.”

The feud spilled over into the weekend when Asselborn accused Salvini of using “methods and tone of the fascists of the thirties,” according to Der Spiegel. “I stand behind what I said,” Asselborn was quoted as telling the German publication.

Salvini, whose anti-immigration stance has made the League the most popular party in currently opinion polls, responded on Sunday with a tweet. “No fascism, just respect of the rules. If they like immigrants so much then they should welcome all of them to Luxembourg, in Italy we have already welcomed too many.”

To contact the reporters on this story: Dan Liefgreen in Milan at dliefgreen@bloomberg.net;Naomi Kresge in Berlin at nkresge@bloomberg.net

To contact the editors responsible for this story: Vidya Root at vroot@bloomberg.net, Marthe Fourcade, Kevin Costelloe

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