But Foreign Minister Abbas Araqchi said after the talks in the Omani capital Muscat that "any dialogue requires refraining from threats and pressure. (Iran) only discusses its nuclear issue ... We do not discuss any other issue with the US".
While both sides have indicated readiness to revive diplomacy over Iran's nuclear dispute, the US wanted to expand the talks to cover the country'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.
Iranian officials have repeatedly ruled out putting Iran's missiles - one of the largest such arsenals in the Middle East - up for discussion, and have said Iran wants recognition of its right to enrich uranium.
For the US, carrying out enrichment - a possible pathway to nuclear bombs - inside Iran is a red line.
Iranian officials have long denied any intent to weaponise nuclear fuel production.
"It was a good start to the negotiations. And there is an understanding on continuing the talks. Co-ordination on how to proceed will be decided in the capitals," Araqchi told Iranian state TV.
"If this process continues, I think we will reach a good framework for an understanding."
Mediator Badr al-Busaidi, Oman's foreign minister, said the talks had been "very serious", with results to be considered carefully in Tehran and Washington DC.
The goal was to reconvene in due course.
Despite the talks, the United States announced on Friday it was sanctioning 15 entities and 14 shadow-fleet vessels connected to illicit trade in Iranian petroleum, petroleum products and petrochemical products.
Iran's clerical leadership remains deeply worried that US President Donald Trump may still carry out his threats to strike Iran after a US naval buildup in seas in the region.
"The lack of trust is a huge challenge during the talks and it should be overcome," Araqchi said.
World powers and regional states fear a breakdown in the negotiations would ignite another conflict between the US and Iran that could spill over to the rest of the oil-producing region.
Iran has vowed a harsh response to any strike and has cautioned neighbouring Gulf Arab countries that host US bases that they could be in the firing line if they were involved in an attack.
There was initially no statement from the United States after the meeting.
The Omani foreign Ministry said al-Busaidi had met separately with Araqchi and with the US delegation led by special envoy Steve Witkoff and Trump's son-in-law Jared Kushner.
"The consultations focused on creating appropriate conditions for the resumption of diplomatic and technical negotiations," the Omani ministry wrote.
with DPA
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