High-level discussions between representatives from Iran and the United States over Tehran's nuclear program concluded Sunday with both sides characterizing them as generally positive.

The US negotiators were "encouraged" by the discussions according to an unnamed US official speaking to the Associated Press and the French news agency AFP.

Talks were reported to have been, "both direct and indirect, and lasted over three hours."

Omani Foreign Minister Badr al Busaidi, who hosted the talks, said they, "included useful and original ideas reflecting a shared wish to reach an honorable agreement."

This latest round of talks took place amid a flurry of diplomatic activity in the region.

Iranian Foreign Minister Abbas Araghchi, who warned against a "strategy of confrontation" in an article published Sunday in the French weekly Le Point, recently visited Saudi Arabia and Qatar and will be in the United Arab Emirates (UAE) on Monday. 

All three will host US President Donald Trump when he visits the region next week on his first major trip abroad since returning to the White House.

What do we know about the talks?

"Agreement was reached to move forward with the talks to continue working through technical elements," the above-cited US official was quoted as saying of the weekend negotiations. 

The source, who spoke on condition of anonymity, said that the next round of talks would take place "in the near future."

Iran's Foreign Ministry spokesperson posted on X that the next round of talks will be coordinated by Oman, site of this fourth round of negotiations.

"The fourth round of indirect Iran-US negotiations is concluded; difficult but useful talks to better understand each other's positions and to find reasonable & realistic ways to address the differences," spokesperson Esmaeil Baqaei said.

This latest round of consultations was led by Iranian Foreign Minister Araghchi and President Trump's global envoy, Steve Witkoff. 

Ahead of negotiations, Araghchi said he hoped the fourth round might bring both sides to "a decisive point."

Both he and Witkoff, however, put down red lines that each said needed addressing before any new nuclear deal could be made to avert future military action.

Nuclear enrichment a 'red line' for both US and Iran 

Witkoff, speaking before Sunday's talks, said Washington's red line would be any enrichment whatsoever of uranium.

"An enrichment program can never exist in the state of Iran ever again," he told the right-wing outlet Breitbart. "That's our red line."

Witkoff added that this means Iran's enrichment facilities in Natanz, Fordow, and Isfahan, "have to be dismantled."

The US Middle East envoy had previously struck different tones, initially suggesting some flexibility on Iran maintaining low-level enrichment for civilian purposes.

Iran itself has stated that its right to enrich uranium for civilian purposes is "non-negotiable."

"Enrichment capability is one of the honors and achievements of the Iranian nation," said Foreign Minister Araghchi in a video before departing to Muscat.

Following Sunday's session he reiterated Iran's stance, saying enrichment, "must continue and there is no room for compromise on it."

Describing this latest meeting as "more serious" than previous rounds, Araghchi told Iranian state television that Tehran may be open to limiting rates of enrichment as a way "to help build trust."

Iran's President Masoud Pezeshkian on Sunday also said calls to dismantle Tehran's nuclear facilities were "unacceptable," adding, "Iran will not give up its peaceful nuclear rights under any circumstances and will not back down from its rights in the face of pressure."

Negotiations 'moving ahead'

Trump, who has threatened military action against Iran if diplomacy fails, will travel to Saudi Arabia, Qatar and the United Arab Emirates on May 13-16.

In his first term as president, he withdrew the US from the nuclear agreement with Iran that allowed the country to enrich uranium at levels well below what is needed for weapons.

Speaking about the negotiations, Trump said he'd rather reach a deal that would see the issue resolved through diplomacy.

"There are only two alternatives: Blow 'em up nicely or blow 'em up viciously," Trump said in an interview on Thursday.

Edited by: Louis Oelofse, Rana Taha