Oman denied reports that it had conveyed a message from the United States to Iran over the downing of a US drone last week. (AP)

Asharq Al-Awsat

Oman denied on Monday reports that it had conveyed a message from the United States to Iran over the downing of a US drone last week.

“The Sultanate is watching current regional developments with concern and hopes that the Iranian and American sides show restraint and address unresolved issues through dialogue,” the foreign ministry also said in a post on Twitter.

Two Iranian sources told Reuters on Friday that US President Donald Trump had warned Tehran via Oman of an imminent US attack, which he later called off, after Iran downed the drone. Trump has denied sending such a message.

Meanwhile, US Special Representative on Iran Brian Hook was in Oman where he told reporters that Washington was looking to agree a treaty that would be ratified by the US Congress, saying the 2015 nuclear accord between Iran and world powers was flawed because it had no legal basis.

“This is a president who is very willing to sit down with the regime,” Hook said.

“I think the question people should be asking is ... why Iran continues to reject diplomacy.”

The United States withdrew last year from the 2015 accord under which Iran accepted curbs to its nuclear program in return for the lifting of sanctions.

Last week the two countries came the closest in years to direct military confrontation after Iran shot down the drone.

Throughout the escalation, both sides have suggested they would be willing to hold talks, but the other side must move first. Iran says the United States must lift the sanctions in reimposed since abandoning the deal last year.

Hook, who accused Tehran of “violent responses to diplomatic pressure,” said Iran could come to the negotiating table or watch its economy “continue to crumble.”

“They are in a recession now, it is going to get significantly worse,” he added hours before Washington announced further sanctions against Tehran, which targeted supreme leader Ali Khamenei and several Iranian Revolutionary Guards officials.

He said there was no diplomatic contact, or back channel, between Washington and Tehran at present.

Hook explained elements of a deal with Tehran would need to involve an end to the arrest of dual nationals in Iran and an end to support for Iranian proxies in the Middle East who committed clandestine attacks on Iran’s behalf.