US special Middle East envoy Steve Witkoff is expected to travel to Oman on Sunday for a fourth round of talks with Iran about its nuclear programme.
The talks come ahead of President Donald Trump's visit to the UAE, Saudi Arabia and Qatar next week.
The latest negotiations will involve both direct and indirect discussions between Washington and Tehran, a source familiar with the matter said.
Mr Witkoff is leading US efforts to reach a deal to end Iran's entire nuclear enrichment programme. Mr Trump in 2018 withdrew the US from a previous deal Tehran signed with world powers. It is not clear if the US is working to force Iran to give up its civilian nuclear programme, or only its alleged push to make weapons-grade uranium.
In an interview with Brietbart on Friday, Mr Witkoff said the US wants Iran to “voluntarily shift” away from an enrichment programme that can reach weapons-grade levels.
“If we can get them voluntarily to do that, that is the most permanent way to make sure that they never get a weapon,” he said.
Mr Witkoff also suggested that the hawkish neoconservative wing of the Republican Party is eager to use military force. Mr Trump has repeatedly threatened force but has appeared reluctant to pursue that path.
“The neo-con element believes that war is the only way to solve things, and the President believes that his force of personality, the way he is going to respond to situations, can bend people to do things in a much better way in the interest of the United States government,” he said. “And I believe in that, too.”
Although both sides have reported progress from the talks, few details have been released. Mr Trump is using a carrot-and-stick approach to get Iran to sign a new deal after he pulled out of the Joint Comprehensive Plan of Action during his first term.
The US President has suggested Iran would be a “great, happy country” if it signs a new deal, but he has also pursued a “maximum pressure” campaign built around tough sanctions aimed at shutting off Iranian oil exports.
Iranian Foreign Minister Abbas Araghchi said that Oman, which has been mediating, had proposed Sunday as the date and both sides had accepted.
“Negotiations are moving ahead and naturally, the more we advance, the more consultations we have, and the more time the delegations need to examine the issues,” he said in a video carried by Iranian media. “But what's important is that we are moving forward so that we gradually get into the details,” Mr Araghchi said.
Western powers accuse Iran of having a clandestine agenda to develop nuclear-weapon capability by enriching uranium to a high level of fissile purity, above what they say is justifiable for a civilian atomic energy programme. Tehran says its nuclear programme is wholly for civilian power purposes.
