Iran has committed a further breach of its nuclear deal with major powers by enriching uranium with advanced centrifuges, and plans to install more of those advanced machines than previously announced, a U.N. nuclear watchdog report showed on Thursday.

Iran is breaching the restrictions of its landmark nuclear deal with major powers step by step in response to U.S. sanctions imposed since Washington pulled out of the agreement last year. The deal only lets Iran accumulate enriched uranium with just over 5,000 of its first-generation IR-1 centrifuges.

The deal also caps the amount of enriched uranium Iran can produce and the purity to which it can enrich it, both of which Tehran has already breached, but only incrementally rather than by ramping up the level and amount as quickly as possible.