(CNN) The European Union's highest court ruled on Monday that Poland must "immediately suspend" a law that forces Supreme Court judges over age 65 to retire.
Critics of Poland's right-wing Law and Justice party, known as PiS, led by Prime Minister Mateusz Morawiecki, said the law was an attempt to take greater control over the judiciary.
In the Law on the Supreme Court, which was introduced in April, the retirement age of Supreme Court judges was lowered from 70 to 65 -- a move pushing 27 of the 72 sitting judges off the bench.
The measure was met by protests across the country and further escalated tensions between the European Union and Poland's government.
In October, the European Union Court of Justice, or ECJ, implemented an interim ruling to scrap the law, and on Monday it upheld that decision until the court can make a permanent one next year.
"Poland must immediately suspend the application of the provisions of national legislation relating to the lowering of the retirement age for Supreme Court judges," the ECJ statement says.
The ECJ's order backs the European Commission, the politically independent executive branch of the EU, in its battle against Warsaw, which it launched in September.
While the final court ruling is due next year, the European Commission felt it necessary to ask the ECJ for interim measures to be applied because the ruling might come too late for the damage to be reversed, a spokesperson for the court said.
Other interim measures in the order include taking "all necessary measures to ensure that the Supreme Court judges concerned by the provisions at issue may continue to perform their duties in the same post" and "refrain(ing) from adopting any measure concerning the appointment of judges to the Supreme Court to replace the Supreme Court judges concerned by those provisions," according to an ECJ statement.