President Donald Trump said that the US had "very good" talks with Iran over Tehran's nuclear programme and confirmed that another meeting will take place next week.
He did not provide more details about the negotiations held in Oman.
"They had a very good meeting with a very high representative of Iran, and we’ll see how it all turns out," Mr Trump told reporters on board Air Force One.
"We’re going to meet again early next week, and they want to make a deal, Iran, as they should want to make a deal."
The US President warned of "steep consequences" if a deal is not reached. Mr Trump signed an executive order, hours after the talks concluded, imposing a 25 per cent tariff on imports from any country that "directly or indirectly" buys goods from Iran.
The White House said the measure is intended to deter third countries from maintaining commercial ties with Iran, particularly in energy, metals and petrochemicals, sectors that remain key sources of revenue for the Iranian government.
Tehran earlier described the talks as "positive" and said there was "near-consensus" on continuing the dialogue in the coming days.
Iran’s Foreign Minister Abbas Araghchi and US special envoy Steve Witkoff were leading the indirect talks, with Oman acting as mediator.
"The atmosphere was positive, and it was a good start," said Mr Araghchi, after meetings lasting about eight hours in Muscat. He said there was a "near-consensus" on continuing talks, but the timing and format had yet to be decided.
The UAE welcomed the US-Iran talks. The Ministry of Foreign Affairs said on Saturday they were a “positive step” reflecting efforts towards dialogue and de-escalation. The UAE also praised Oman's role in “creating a conducive environment for dialogue”.
On Saturday the office of Israeli Prime Minister Benjamin Netanyahu said he is expected to meet Mr Trump in Washington on Wednesday and that the Iran talks would be on the agenda. It said Mr Netanyahu believes any negotiations "must include limitations on ballistic missiles and a halting of the support for the Iranian axis". Iranian officials have threatened to launch military strikes on Israel in the event of a fresh attack on Tehran by the US.
Washington wants the Iran talks to include Tehran’s ballistic missile programme, its backing of regional armed groups and its domestic record, US Secretary of State Marco Rubio said on Wednesday. Iran, however, has said the Muscat talks should be limited to nuclear issues.
The Iranian Foreign Minister added that "the subject of our talks is strictly nuclear, and we are not discussing any other issues with the Americans".
Stakes were high amid fears that a failure in the negotiations could ignite a large-scale war in the Middle East. In June last year, the US struck Iranian nuclear sites, joining in the final stages of a 12-day Israeli bombing campaign. Tehran has since said its uranium enrichment work has stopped. Tehran's leadership remains deeply concerned that Mr Trump may still carry out his threats to strike Iran amid a build-up by the US Navy near Iran.
But a recent diplomatic push by Arab and Gulf states helped to keep the meeting in Muscat on track, after disagreements over the format and venue threatened to derail it.
Even as the US engages in diplomatic talks with Iran, the White House is seeking input from prominent Iranian Americans who could assist in any transition should supreme leader Ayatollah Ali Khamenei be toppled, sources said.
A source close to American efforts to find an alternative to the current regime in Iran told The National that Mr Trump's son-in-law Jared Kushner is closely involved.
He is helping to assemble a group of Iranian-American business leaders to advise on the formation of some sort of transitional entity to help govern Iran in the event of the regime's collapse, the source said.
A second source also said Mr Kushner is involved, but White House deputy press secretary Anna Kelly denied it. "This is false," she said.
An exact date for next week's talks has yet to be announced.
