Oman's foreign minister said "significant progress" had been made in talks between US and Iranian officials in Geneva.

The mediator said the chances of reaching a deal that would avert war were still unclear.

Omani Foreign Minister Badr Albusadi, who was the mediator in the indirect talks between the two sides, said US and Iranian negotiators had decided to resume talks "soon" after consulting their leaders, and that technical discussions would be held in Vienna next week.

Iranian Foreign Minister Abbas Araghchi said there had been "good progress" and that while there was agreement on some issues, differences remained on others.

The next round of talks is expected in less than a week, they said.

Further talks between the two countries could reduce the chances of President Donald Trump carrying out his threat to attack.

Trump has ordered the largest military deployment to the Middle East since the 2003 US invasion of Iraq.

Iran has warned it will respond if attacked.