This “is a matter of serious concern, as you can understand, because we as the European Union are steadfast supporters of the International Criminal Court,” Josep Borrell, the EU’s foreign policy chief, said in an online press conference after a virtual meeting with foreign affairs ministers from the Eastern Partnership countries(Armenia, Azerbaijan, Belarus, Georgia, Moldova and Ukraine).

The U.S. decision comes after Trump has withdrawn from a string of international agreements that are important for the EU including the Paris climate accord and the Iran nuclear deal. He’s also ended cooperation with the World Health Organization and pulled out of the United Nations Human Rights Council.

Borrell said that “he learned this very bad news” when the video meeting was coming to an end, adding that, because of this, “my answer has to be cautious because I don’t know exactly the extent of this decision.”

Yet he didn’t hold back. “I think that for sure I can reiterate our support to this institution,” the former Spanish minister said, stressing that the Hague-based tribunal has been playing a key role in addressing “the greatest international crimes.” The ICC, he added, “is a key factor in bringing justice and peace, it must be respected and supported by all nations and we’ll analyze the decision in order to assess its full implications.”

The Foreign Affairs Council, which gathers all EU foreign affairs ministers, will meet on Monday and “will have their say about it, but from my point of view immediately … I just want to reaffirm our support to the court,” Borrell said.