Iran's nuclear chief announced Monday the country is operating dozens of advanced centrifuges in a move that further goes against the 2015 agreement the country signed with a group of world powers.

Ali Akbar Salehi, the head of Iran's Atomic Energy Organization, said told state television Monday that Iran was operating the IR-6 centrifuges, which allow the processing of uranium much faster than the IR-1 centrifuges Iran was allowed to used under the nuclear deal.

Salehi also said Iran was working on the development of even faster centrifuges.

The 2015 agreement called for Iran to limit its nuclear activity in response to allegations it was working on a nuclear weapons program. Iran said its nuclear work was solely for peaceful purposes, but agreed to the conditions in exchange for badly needed relief from economic sanctions.

Since U.S. President Donald Trump withdrew from the agreement last year, Iran has taken several steps back from its commitments, including exceeding limits on the amount of enriched material it is allowed to stockpile and the level to which it is allowed to enrich uranium.

Iran has complained the other signatories, particularly European nations, have not done enough to help it achieve sanctions relief after the United States imposed new sanctions.