If European parties to the agreement "do certain strange acts then we would skip all the next steps (in the plan to scale back commitments) and implement the last one," foreign ministry spokesman Abbas Mousavi said.

He did not specify what the final step would be.

Iran said Sunday it was hours away from breaching the uranium enrichment limit, stepping back from another commitment more than a year after the United States pulled out of the nuclear accord.

Asked if Tehran could withdraw entirely from the deal, Mousavi said "all the options" were possible but "no decision has been taken".

France, Germany and Britain -- the remaining Europeans partners of the international deal -- have urged Tehran to halt its advance towards breaching the cap.

But Iran says it has lost patience with a perceived lack of action by the European side to help Tehran economically in the face of crippling US sanctions.