Iran said on Sunday it will boost its uranium enrichment in a few hours above a cap set by the nuclear deal, a move that could eventually culminate in the return of all international sanctions on Tehran.
"Iran has broken the terms of the JCPoA," the Foreign Office spokesman said, refering to the deal's formal name, the Joint Comprehensive Plan of Action (JCPOA).
"While the UK remains fully committed to the deal, Iran must immediately stop and reverse all activities inconsistent with its obligations. We are coordinating with other JCPoA participants regarding the next steps under the terms of the deal, including a Joint Commission."