UNITED NATIONS, Jan. 17 (Xinhua) -- UN Secretary-General Antonio Guterres on Wednesday stressed the importance of an international deal on Iran's nuclear issue on the second anniversary of the implementation of the agreement.

"The secretary-general remains convinced that the JCPOA (Joint Comprehensive Plan of Action) is the best way to ensure the exclusively peaceful nature of Iran's nuclear program and to realize the promised tangible economic benefits for the Iranian people," said Guterres' spokesman Stephane Dujarric in a statement.

JCPOA refers to the Iran nuclear deal reached in Vienna in July 2015 between Iran and the five permanent members of the UN Security Council plus Germany.

"The JCPOA constitutes a major achievement of nuclear non-proliferation and diplomacy, and has contributed to regional and international peace and security," said the statement.

The secretary-general noted that UN nuclear watchdog, the International Atomic Energy Agency, has repeatedly confirmed that Iran is fulfilling its nuclear-related commitments under the deal, it said.

U.S. President Donald Trump on Friday waived nuclear sanctions against Iran, but warned that he would not do it again unless the deal is to be fixed. Tehran has said it will not renegotiate the nuclear deal.

Under the agreement, Iran agreed to limit its nuclear program in exchange for the lifting of international sanctions.