The European Commission says a move to reduce the age at which Poland's Supreme Court judges must retire will undermine judicial independence, breaching the country's obligations under EU law.
The EU on Monday launched legal action against Poland over its controversial Supreme Court reforms, in the latest round of a bitter spat between Brussels and the right-wing government in Warsaw.
The European Commission, the bloc's powerful executive arm, said a move to reduce the age at which Supreme Court judges must retire from 70 to 65 would undermine judicial independence, breaching Poland's obligations under EU law.
The commission has been in talks with Warsaw about several judicial reforms that the EU says threaten the rule of law in Poland, but they said swift action was needed on the Supreme Court issue.
"While the Polish Supreme Court law has already been discussed in the context of the rule of law dialogue between the commission and the Polish authorities, it has not been satisfactorily addressed through this process," European Commission spokesman Margaritis Schinas told reporters.
Forced to step down
The new retirement age, introduced by Poland's Law and Justice (PiS) government, comes into force on Tuesday and would force more than a third of current Supreme Court judges to step down.
"Given the lack of progress and the imminent implementation of the new retirement regime for supreme court judges, the commission decided to launch the infringement procedure today as a matter of urgency."
In a separate statement, the commission said it took the view "that these measures undermine the principle of judicial independence, including the irremovability of judges."
The PiS government insists the changes are needed to tackle corruption and overhaul a judicial system still haunted by the communist era, but critics including the EU argue they undermine the division of powers and therefore threaten democracy and the rule of law.
In December Brussels triggered unprecedented Article 7 proceedings against Poland over "systemic threats" to the rule of law, which could eventually see Warsaw's EU voting rights suspended.
Poland has a month to respond to the commission's formal announcement, the first stage of a procedure that could end up in the European Court of Justice, the bloc's top tribunal.
Several dozen Polish Supreme Court judges last week vowed to defy the reforms and stay in office after Tuesday, arguing that the government reforms were unconstitutional.