Germany on Wednesday criticized Iran’s recent move to start enriching uranium at an underground facility and urged Tehran to return to full compliance with the 2015 nuclear agreement.

“This is unacceptable,” German Foreign Minister Heiko Maas told a news conference in Berlin, referring to Iranian President Hassan Rouhani’s announcement that Iran was beginning injecting gas to 1,044 centrifuges at its Fordow nuclear facility.

“This step is incompatible with Iran’s obligations under the nuclear deal. By this, Iran continues to put at stake the agreement,” Maas warned.

“So we strongly urge Iran to reverse all steps that have been taken

Read more: Germany says Iran’s nuclear move ‘unacceptable’