US President Donald Trump has warned the Iranian President to be careful, after Hassan Rouhani was quoted as saying that anyone who speaks to Iranians with threats would regret. <br/><br/>The US President was replying to a query on a special flight, about Mr Rouhani's reported remarks to a rally in Tehran to celebrate the anniversary of the Islamic Revolution. Earlier this month, Mr Trump put Iran on notice over charges that Tehran violated a nuclear deal with the West by test-firing a ballistic missile.