Iran has explicitly signaled its intent for the first time to quit its nuclear deal in announcing it would start injecting uranium gas at an enrichment facility, French President Emmanuel Macron has said.

Speaking at a press conference at the end of a visit to China on Wednesday, Macron called Iran’s latest move “grave,” Reuters reports.

“I think that for the first time, Iran has decided in an explicit and blunt manner to leave the JCPOA (nuclear) agreement, which marks a profound shift,” said Macron.

The French president has been at the forefront of European efforts to salvage the deal after the United States withdrew from the agreement.