Iran will ban Americans from entering the country in response to President Donald Trump's "insulting" order restricting arrivals from Iran and six other Muslim states, the foreign ministry said Saturday.
"The Islamic Republic of Iran... has decided to respond in kind after the insulting decision of the United States concerning Iranian nationals", the ministry said in a statement carried by state television.
Trump on Friday signed a sweeping executive order to suspend refugee arrivals and impose tough controls on travellers from Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen.
Iran's foreign ministry called the decision "illegal, illogical and contrary to international rules".
It said its own ban on US nationals would continue until the American measure was lifted.
It said it had ordered Iranian diplomatic missions to help Iranians who had been "prevented from returning to their homes and places of work and study" in the United States.
Travel agents in Tehran said that foreign airlines had begun barring Iranians from US-bound flights.