By Joanna Plucinska and Sabine Siebold

WARSAW (Reuters).-The European Union was plunged into an existential crisis Friday by a Polish court that challenged the supremacy EU law. This led to the possibility for Poland’s exit from the 27-nation bloc.

Europe’s politicians expressed dismay at the attempt to weaken the EU’s legal pillar. One minister warned the country in eastern Europe that the court was “playing with fire”.

Ursula von der Leyen was the President of the European Commission. She stated that she was deeply concerned by Thursday’s decision by Poland’s Constitutional Tribunal. The executive she heads would do everything in her power to protect the supremacy of EU law.

The Polish prime minister welcomed the decision of the court and said that his country would like to remain in the rich trade and political organization it joined in 2004, but each state should be treated with equal respect.

Brussels and Warsaw have been in conflict for years over democracy standards and independence of the judiciary. However, Thursday’s decision that certain parts of EU law were incompatible with the Polish Constitution put Warsaw and Brussels into a complete collision.

On arrival at a Luxembourg meeting of EU ministers, Jean Asselborn stated that “We must clearly state that this government is playing with fire.”

For the integration of Europe, and for living together in Europe, it is vital that European law has primacy. Europe, the way we know and built it with the Rome treaties will end if this principle is violated.

Clement Beaune, French Minister for European Affairs, stated that the ruling by the Polish Constitutional Tribunal was an attack against the EU and could result in economic sanctions being imposed on Warsaw.

“It’s most serious… Beaune stated that there is a de facto possibility of Poland leaving the European Union.

NO PLANS FOR “POLEXIT”

The Law and Justice party in Poland (PiS), which is headed by the Law and Justice Party, says that it does not plan to “Polexit”. Unlike Britain’s Brexit vote in 2016, Poland has high support for EU membership.

The Constitutional Tribunal was appointed to handle the case by Prime Minister Mateusz Morawiecki, who asked if EU institutions were able to stop Poland from reorganizing its judiciary.

We want to create a community that respects others and not just a collection of people who are more or less equal. “This is our Union, this is our community,” Morawiecki stated on Facebook (NASDAQ : ), in reference to the EU. “This Union is the one we desire and this Union will be ours.”

Von der Leyen stated in a statement, that legal certainty is essential for the EU’s more than 450 million citizens. Her executive will use every power it holds under EU treaties and ensure that EU law prevails over all national laws.

The Commission will conduct a quick analysis in order to determine its next steps, she said. Officials in Brussels claimed that Warsaw could face a number of civil and criminal cases. This process will be lengthy.