US Ambassador Nikki Haley has said that Iran should not be allowed to use the nuclear deal to hold the world hostage. She 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.<br/><br/>Earlier, Iran's President Hassan Rouhani warned that it could restart its nuclear programme within hours, if the United States imposes any more new sanctions. He also said the programme would be more advanced than what it was in 2015, when Iran curbed its nuclear activities as part of a deal with world powers.<br/><br/>Iran said unilateral US sanctions targeting its ballistic missile programme breach the agreement. However, the US says Iran's missile tests have violated a UN resolution. <br/><br/>The resolution endorsed the nuclear deal and called upon Iran not to undertake any activity related to ballistic missiles designed to be capable of delivering nuclear weapons, including launches using such ballistic missile technology.<br/><br/>Tehran on the other hand says the missiles it has tested are not designed to carry nuclear warheads and insists its nuclear programme is entirely peaceful. <br/><br/>It may be recalled that Iran's Parliament on 13th August voted in favour of boosting investment in its missile defence and foreign operations programmes by more than 500 milliion dollars. <br/><br/>The vote came after the United States imposed fresh US sanctions against Iran in July, targeting its missile programme.