The EU took the Czech Republic, Hungary and Poland to the bloc's top court Thursday over their refusal to accept quotas for asylum-seekers, setting up a new clash between Brussels and key eastern states.
The move shows the determination in Brussels to enforce the controversial scheme launched at the height of the migrant crisis in 2015 to share 160,000 refugees around the bloc and ease the burden on Greece and Italy.
"The European Commission has today decided to refer the Czech Republic, Hungary and Poland to the Court of Justice of the EU for non-compliance with their legal obligations on relocation," the commission said in a statement.
There was no immediate reaction from Prague, Budapest or Warsaw, but all three have previously said the quotas are part of attempts by Brussels to limit national sovereignty.
Brussels launched so-called infringement proceedings against the three countries in June for failing to take in any refugees under the quota system, and warned them last month of further action.
They face heavy fines for failing to comply with any eventual ruling by the Luxembourg-based European Court of Justice.
The ongoing row over the quota scheme has held up efforts to reform the bloc's asylum system, which leaders are supposed to be discussing at an EU summit in Brussels on December 14-15.
The EU's "relocation" scheme is now wrapping up having moved 32,000 out of an originally planned total of 160,000, but it caused bad blood when it was forced through two years ago despite the objections of some countries.
The row also underscores a growing rift between western European states and newer, former Soviet-bloc states in the European Union over a series of issues from migration to democratic standards.
- Hungary in the crosshairs -
Budapest faced a triple legal whammy from Brussels on Thursday, with the European Commission also taking Hungary to the ECJ over a crackdown on education and foreign-backed civil society groups that critics say targets US billionaire George Soros.
The European Commission -- the executive arm of the EU -- said Hungary had repeatedly failed to answer its concerns over both cases.
It said in a statement that it was suing Hungary as the education law "disproportionally restricts EU and non-EU universities in their operations and needs to be brought back in line with EU law."
Hungary has introduced an education law that could shut the Soros-founded Central University in Budapest, which has long been seen as a hostile bastion of liberalism by Orban's right-wing government.
In June, Hungary approved a law aimed at forcing civil society groups receiving more than 24,000 euros ($26,000) annually in overseas funding to register as a "foreign-supported organisation", or face closure.
The European Commission said that the laws on foreign non-governmental organisations "indirectly discriminate and disproportionately restrict donations from abroad to civil society organisations."
Poland's rightwing government is also in the EU's legal crosshairs.
Last month the ECJ warned Warsaw to stop logging in one of Europe's last primeval forests "immediately" or face fines of up to 100,000 euros a day.
The European Parliament also voted to start an EU sanctions procedure over Warsaw's controversial judicial reforms that could eventually suspend Polish voting rights in the bloc.