US President Donald Trump has issued a stern warning to Iran, saying the country is under close surveillance and a "massive fleet" is being deployed to the Gulf region. Speaking to reporters aboard Air Force One on Thursday, following his return from the World Economic Forum in Davos, Trump stressed that any aggressive action by Tehran would trigger a severe response.

Iran has issued a stark warning to US President Donald Trump that it would treat any American attack as an all-out war, just a day after Trump announced a big force of warships was heading towards the violence-hit Middle East nation.