Serbia has urged its citizens in Iran to leave the country “as soon as possible”, after US President Donald Trump threatened military action over the Islamic republic’s nuclear program.The Balkan nation had already invited Serbian nationals in mid-January to leave Iran and not to travel there, as the country’s clerical authorities launched a bloody crackdown on a mass protest movement.For all the latest headlines follow our Google News channel online or via the app.“Due to the deteriorating security situation, citizens of the Republic of Serbia are not recommended to travel to Iran in the coming period,” the foreign ministry said in a statement on its website published overnight Friday to Saturday.“All those who are in Iran are recommended to leave the country as soon as possible.”Iran said on Friday that it was hoping for a quick deal with the United States on Tehran’s nuclear program, long a source of discord between the two foes.But Trump, after ordering a major naval build-up in