TEHRAN, Oct. 30 (Xinhua) -- Iran will "definitely" take the fourth step to reduce its nuclear commitments if its demands are not met in the negotiations with the remaining members of the 2015 nuclear deal, Iranian President's Chief of Staff Mahmoud Vaezi said on Wednesday.

Iran has established a committee that is in charge of plans for the fourth step in reducing commitments, Vaezi told reporters on the sidelines of cabinet meeting.

"If Europe does not fulfill its commitments (to help Iran take benefit from the nuclear deal), Iran will take the fourth step in due time," he stressed.

Since May, Iran has made three moves to build stockpiles of nuclear fuel and enrich low-grade uranium to a higher level of purity, and has started up advanced centrifuges to boost the country's stockpile of enriched uranium, which had been restricted by the accord.

Iran's moves were a reaction to the U.S. unilateral withdrawal from the deal, also known as the Joint Comprehensive Plan of Action (JCPOA), last year and the reimposition of sanctions against the Islamic Republic.