Iran's U.N. ambassador is accusing the United States of violating the Nuclear Nonproliferation Treaty by modernizing its nuclear weapons instead of moving toward disarmament.

Ambassador Majid Takht Ravanchi cited progress in achieving a universal ban on nuclear explosions and the broader objective of nuclear disarmament but said "unfortunately, currently, there are two alarming races: new nuclear arms race and nuclear arms modernization race."

He told Monday's U.N. General Assembly's commemoration of the International Day Against Nuclear Tests that "irresponsible policies" like those of the U.S. "are detrimental to all international efforts towards nuclear disarmament and non-proliferation, and therefore must come to an end."

Ravanchi stressed that voluntary moratoriums on nuclear testing "cannot substitute for a comprehensive universal and verifiable legally binding prohibition on all types of nuclear explosions, including in alternative ways."

He urged redoubled effort to pursue "the noble objective of the total elimination of nuclear weapons."