Following a series of steps away from its commitments under the 2015 accord, the head of the Iranian atomic energy agency said Monday that production of enriched uranium had reached five kilos a day and two new advanced centrifuges had been developed.

Maja Kocijancic, spokeswoman for EU diplomatic chief Federica Mogherini, said the bloc "took note" of the announcement but would wait for confirmation by the UN International Atomic Energy Agency before responding.

"We have continued to urge Iran to reverse such steps without delay and to refrain from other measures that would undermine the nuclear deal," Kocijancic told reporters in Brussels, saying the EU "remained committed" to the nuclear deal.

"But we have also been consistent in saying that our commitment to the nuclear deal depends on full compliance by Iran."

Tehran decided in May to suspend certain commitments under the accord, a year after US President Donald Trump withdrew from the deal and reimposed sanctions on the Islamic republic.

Iran has so far hit back with three packages of countermeasures and threatened to go even further if the remaining partners to the deal -- Britain, China, France, Germany and Russia -- fail to help it circumvent US sanctions.