Iranian Foreign Minister Mohammad Javad Zarif today criticised US President Donald Trump for sealing an arms deal and other investments worth hundreds of billions of dollars with Saudi Arabia. <br/><br/><br/>Zarif's comments came hours after Trump, who is visiting Saudi Arabia, urged Arab and Islamic leaders to unite and defeat Islamist extremists. Trump singled out Iran as a key sponsor of militant groups, sending a tough message to Tehran the day after Hassan Rouhani won a second term as Iran's president.'<br/>'<br/>Iran and Saudi Arabia have long accused each other of sponsoring militias aligned to their competing sects of Islam in conflicts across the Middle East.<br/>'<br/>Introducing Trump, Saudi King Salman described Tehran as a mutual foe and a source of terrorism they must confront together.<br/>'<br/>In his first keynote speech abroad, Trump sought to redefine his relationship with the Muslim world, and focused on his desire to curb Iran's influence in the region.