The UK called Iran's starting of centrifuges “particularly disappointing” on Saturday, following an announcement from Iran that it will start up advanced centrifuges to boost the country's stockpile of enriched uranium.

“This third step away from its commitments under the nuclear deal is particularly disappointing at a time when we and our European and international partners are working hard to de-escalate tensions with Iran,” the Foreign Office said in a statement.

Iran's atomic energy organization spokesman Behrouz Kamalvandi stated earlier on Saturday that Iran is injecting uranium gas into advanced centrifuges, breaking a new atomic deal term. He stated that in next two months, 164 chain machines of IR4 centrifuges will become operational, adding that 20 are already operational.