President Donald Trump says he would "certainly meet" with Iranian President Hassan Rouhani if the Iranian leader was willing, adding he would do it with "no preconditions."

Trump says during a joint news conference with Italy's leader that he believes in meetings and is pointing to the benefits of recent meetings with North Korea's Kim Jong Un and Russia's Vladimir Putin.

The Trump administration withdrew from the landmark nuclear accord with Iran in May, saying it was too generous to Iran. The United States has vowed to boost sanctions until Iran changes its regional policies, including its support for regional militant groups.