The US president says he has proposed talks on a deal to prevent Iran acquiring nuclear weapons and to avert military action.

A letter from U.S. President Donald Trump to Iran's clerical establishment has been delivered by Anwar Gargash, diplomatic adviser to the president of the United Arab Emirates, Iran's foreign ministry spokesperson and state media said on Wednesday.

While the UAE seeks a greater mediator role in the region, covert rivalries among Gulf states and fragile Emirati-Iranian ties may limit its role.