Nuclear talks between Iran and the United States held in Oman on Friday were a good beginning and will continue, Iran’s foreign minister said, after growing concerns that a failure in the high-stakes negotiations could set off another Middle East war.

“It was a good start to the negotiations. And there is an understanding on continuing the talks. Coordination on how to proceed will be decided in the capitals,” the minister, Abbas Araghchi, told Iranian state TV. “If this process continues, I think we will reach a good framework for an understanding.”

Officials from both sides, who held indirect talks through Omani mediation in Oman’s capital Muscat, will return home for consultations, Araqchi said.

While both sides have indicated readiness to revive diplomacy over Tehran’s long-running nuclear dispute with the West, Washington wanted to expand the talks to cover Iran’s ballistic missiles, support for armed groups around the region and “treatment of their own people”, US Secretary of State Marco Rubio said on Wednesday.

Araqchi told Iran’s state news agency IRNA that “any dialogue requires refraining from threats and pressure”, adding that Tehran “only discusses its nuclear issue. We do not discuss any other issue with the US”

Iranian officials have repeatedly said they will not discuss Iran’s missiles — one of the biggest such arsenals in the region — and have said Tehran wants recognition of its right to enrich uranium. For Washington, carrying out enrichment inside Iran is a red line.

Tehran’s clerical leadership remains deeply worried that Trump may still carry out his threats to strike Iran after a military buildup by the US Navy near Iran.

“The lack of trust is a huge challenge during the talks and it should be overcome,” Araqchi said.

In June, the US struck Iranian nuclear targets, joining in the final stages of a 12-day Israeli bombing campaign. Tehran has since said its uranium enrichment work has stopped.

The US naval buildup, which Trump has called a massive armada, has followed a crackdown on nationwide protests in Iran last month, heightening tensions between Washington and Tehran.

Trump has warned that “bad things” would probably happen if a deal could not be reached, ratcheting up pressure on the Islamic republic in a standoff that has led to mutual threats of air strikes.

World powers and regional states fear that a breakdown in the negotiations would lead to another conflict between the US and Iran, which could spill over to the rest of the oil-rich region.

Iran has vowed a harsh response to any military strike and has cautioned neighbouring Gulf Arab countries hosting US bases in the oil-rich region that they could be in the firing line if they were involved in an attack.

Negotiators in Oman will have to navigate Iran’s red line on discussing its missile programme to reach a deal and avert future military action. Tehran has flatly ruled out talks on its “defence capabilities, including missiles and their range.”

In a show of defiance, Iran’s state TV said hours before the talks that one of the country’s most advanced long-range ballistic missiles, the Khorramshahr-4, had been deployed at one of the Revolutionary Guard’s vast underground missile cities.

However, Tehran is willing to show “flexibility on uranium enrichment, including handing over 400 kilogrammes of highly enriched uranium (HEU) and accepting zero enrichment under a consortium arrangement as a solution,” Iranian officials told Reuters last week.

Iran also demands the lifting of sanctions, reimposed since 2018 when Trump ditched Iran’s 2015 nuclear deal with six powers.

The US, its European allies and Israel accuse Tehran of using its nuclear programme as a veil for efforts to try to develop the capability to produce weapons. Iran says its nuclear programme is for peaceful purposes only.

Israel has likened the danger of Iran’s missiles to its nuclear programme. Prime Minister Benjamin Netanyahu said in January that Iran’s “attempt to build atomic weapons” and “20,000 ballistic missiles” were like “two lumps of cancer”.