US President Donald Trump said he would prefer a diplomatic agreement with Iran to military conflict.

Speaking to journalists aboard Air Force One, Trump said he did not want people to be killed and wanted to reach a deal.

Trump said indirect, mediated talks between the United States and Iran were expected to begin.

He said a war would be disastrous for Iran.

Trump said a military operation had been temporarily paused after contacts involving Saudi Arabia, the United Arab Emirates, Qatar and Iran, and because he saw a possibility of an agreement.

He linked a potential agreement to the full reopening of the Strait of Hormuz and progress toward dismantling Iran's nuclear programme.

Trump did not set a timetable for negotiations.

He also reiterated that the United States was prepared to take military action if necessary.