United States Secretary of State Mike Pompeo says Iran will face further sanctions in response to its expected breach of a uranium enrichment cap.
On Sunday, Iran said it was hours away from breaching the cap set by an endangered nuclear deal reached with international powers but from which the United States withdrew last year.
Iran also threatened to abandon more of its commitments unless a solution is found with parties to the landmark 2015 agreement.
The deal saw Iran commit not to acquire an atomic bomb, to accept drastic limits on its nuclear programme and to submit to International Atomic Energy Agency inspections in exchange for a partial lifting of crippling international sanctions.
