Poland has a legal and moral obligation as a member of the European Union to abide by the bloc’s rules completely and unconditionally, the foreign ministers of France and Germany said in a joint statement issued on Friday.

Poland’s Constitutional Tribunal on Thursday ruled that parts of EU law are incompatible with the Polish constitution, undermining the legal pillar on which the 27-nation EU stands, and prompting expressions of dismay from politicians across Europe.

The joint statement, issued by French Foreign Minister Jean-Yves Le Drian and his German counterpart Heiko Maas, said the ministers had taken note of the Polish tribunal’s decision.

“We remind you that membership of the European Union goes hand in hand with a complete and unconditional adherence to common values and rules,” the statement said.

“It is incumbent on each member, and therefore of course on Poland, which occupies a vital place within the European Union, to respect these rules and values.”

“This is not simply a moral commitment. It is also a legal commitment,” the statement said.