Haley said Iran must be held responsible for launching missiles, supporting terrorism, disregarding human rights and violating UN Security Council resolutions. (Photo: File)

United Nations: US Ambassador Nikki Haley says Iran should not be allowed "to use the nuclear deal to hold the world hostage."

Haley commented on Tuesday after Iranian President Hassan Rouhani warned that the landmark 2015 nuclear agreement with the US and five other world powers could fall apart. Rouhani said Tehran could quickly ramp up and advance its nuclear program if the US continues "threats and sanctions" against Iran.

Haley warned that "the nuclear deal must not become 'too big to fail.'" She added that "Iran, under no circumstances, can ever be allowed to have nuclear weapons."

Haley said Iran must be held responsible for launching missiles, supporting terrorism, disregarding human rights and violating UN Security Council resolutions. She plans to visit the UN nuclear agency in Vienna next week.