Qatari mediators presented Iran with a new draft deal on Sunday to end the war with the US and Israel, and Tehran is expected to send a response to the draft by the end of the week, an official briefed on the negotiations said on Wednesday.
The new draft being considered by Iran sets a seven-day timeline addressing both Tehran's and Washington's concerns, laying out daily confidence-building steps that each side must take, the official said.
The timeline could begin early next week, and several countries would act as guarantors of the deal, the official added.
Qatar, along with Pakistan, has led mediation to end the war that the US and Israel launched in February. The conflict has disrupted global shipping and oil supplies and spilled over across other parts of the Middle East.
There were concerns ahead of Sunday's meeting in Tehran that Israeli Prime Minister Benjamin Netanyahu, fighting for another term in a general election, could resume attacks on the Islamic Republic this week, the official briefed on the negotiations said.
Trump threatens to resume strikes on Iran
On Friday, US President Donald Trump repeated threats to strike Iran again, while Iranian security officials told Reuters Tehran had drawn up detailed plans to attack Gulf undersea cables if the US and Israel resumed attacks.
Earlier mediation efforts helped produce an interim peace agreement in June, but the deal quickly unraveled.
In recent weeks, Yemen's Iran-aligned Houthis have launched repeated attacks against Saudi Arabia, the world's largest crude exporter.