Members of the centre-right European People's Party have officially requested the exclusion of Hungary's populist Prime Minister Viktor Orban and his Fidesz party from the group, a top official said Monday.
Three months from the European Parliament election, the move reflects growing sentiment in the assembly's dominant bloc that Hungary's nationalist leader goes against EU values.
Also infuriating EPP members was a campaign in Hungary targeting European Commission President Jean-Claude Juncker, also of the EPP, who is accused of supporting illegal migration.
Budapest said on Saturday that it would put an end to the controversial campaign.
"Twelve EPP member parties from nine countries have requested the exclusion or suspension of Fidesz," party leader Joseph Daul told AFP, adding that the question will be discussed at a meeting on March 20.
"The decision rests with all EPP members and I cannot anticipate the outcome of the discussion," Daul added.
The EPP is the biggest party in the European Parliament, and comprises the main centre-right movements in Europe, including German Chancellor Angela Merkel's CDU and France's Les Republicains, which have not moved against Orban.
The EPP was obliged to launch the process once the threshold of at least seven member parties from five different countries was passed.
"We must give Fidesz the opportunity to express itself. Once again, I cannot prejudge the conduct of the debates," Daul said.
On the list opposing Orban are Belgian parties CD&V and cdH, Finland's Kokoomus, Greece's New Democracy, Lithuanian TS/LKD and Luxembourg's CSV.
Also against the leader are CDA of the Netherlands, the Portuguese parties CDS-PP and PSD, Sweden's Kristdemokraterna and Moderaterna, as well as Norway's Hoyre.
The EPP party assembly will take place on the eve of a two-day summit of EU leaders, which will be dominated by Brexit.
Any decision to expel Orban will be fraught ahead of the elections to the European Parliament scheduled for May 23-26, in which the Hungarian populists hard stance on migration is seen by some as a vote winner.
If the Fidesz is thrown out, however, some in the EPP fear that Orban will ally with the Northern League of Italian Interior Minister Matteo Salvini.
But the Hungarian government's direct attack on Juncker's Commission -- with the launch of an anti-immigrant, eurosceptic campaign -- increased the pressure on the EPP to act.
Merkel last month voiced full backing for Juncker in the widening row with Hungary's Orban.
Separately, Manfred Weber, the EPP's leading candidate to take over as head of the Commission later in the year, also took Juncker's side in the rift roiling the conservative group.
Hungarian Prime Minister and Chairman of FIDESZ party Viktor Orban, pictured in February 2019