An adviser to Iran's supreme leader has warned that the country will have 'no choice' but to acquire nuclear weapons if it is attacked by the United States or its allies. The warning comes after US President Donald Trump threatened to bomb Iran if it did not make a deal to curb its nuclear program. Iran's supreme leader, Ayatollah Ali Khamenei, promised to hit back if Trump carried out the threat. Despite the sharpening of Trump's comments, it is not clear if he was threatening a US bombing or an operation coordinated with another country, possibly Israel.