In Washington, State Department spokeswoman Tammy Bruce said a meeting in Rome on Saturday between the United States and Iran had never been confirmed.

"We expect another round of talks that will take place in the near future," Bruce said.

Both Iran and the United States had reported progress in three rounds of talks on consecutive Saturdays since April 12.

"The next round of indirect Iran-US talks, which were scheduled to be held in Rome on Saturday... has been postponed," foreign ministry spokesman Esmaeil Baqaei said in a statement on Thursday.

He said the decision had been taken "based on the proposal of the Omani minister".

Omani Foreign Minister Badr Albusaidi cited "logistical reasons" for the delay.

"For logistical reasons, we are rescheduling the US-Iran meeting provisionally planned for Saturday May 3. New dates will be announced when mutually agreed," he said on X.

Iranian diplomats had also been due to meet in Rome on Friday with representatives of Britain, France and Germany.

However, French Foreign Minister Jean-Noel Barrot told AFP in Washington these talks will not now take place.

"A technical meeting was planned prior to... (the) meeting between the United States and Iran," Barrot said in an interview.

"Since that meeting is not taking place, the technical meeting is no longer relevant, at least at that time," Barrot added.

During his first term, US President Trump unilaterally withdrew from the painstakingly negotiated 2015 nuclear deal which also included Britain, China, France, Germany and Russia.

Since returning to office in January, Trump has revived his "maximum pressure" policy towards Tehran.

In March, he wrote to Iran's supreme leader Ayatollah Ali Khamenei proposing talks but warning of possible military action if diplomacy failed.

Western governments have long accused Iran of seeking to acquire a nuclear weapons capability -- an ambition Tehran has consistently denied, insisting its programme is for peaceful purposes only.

Despite the three rounds of Iran-US negotiations, Washington has continued to impose new sanctions targeting Tehran's nuclear programme and its oil network, the latest being announced on Wednesday.

Iran's foreign ministry condemned what it called "the contradictory approach of American decision-makers and their lack of goodwill and seriousness in advancing the path of diplomacy".

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