Iranian President Hassan Rouhani on Tuesday ruled out holding any bilateral talks with the US and threatened to further cut Iran's commitments to a nuclear deal within days.

In an address to parliament, Rouhani said any dialogue with the US would have to fall within the framework of the group of major powers that agreed the landmark nuclear deal with Iran in 2015.

Rouhani also said Iran was ready to further reduce its commitments to the accord "in the coming days" if current negotiations with European nations yield no results by Thursday.

Tehran and Washington have been at loggerheads since May last year when US President Donald Trump unilaterally withdrew from the nuclear deal and began reimposing crippling sanctions.

The arch-foes were on the cusp of confrontation in June when Iran downed a US drone and Trump ordered retaliatory strikes before cancelling them at the last minute.

France has been leading efforts to calm the situation, with President Emmanuel Macron expressing hope during G7 talks in late August of organizing a meeting between Rouhani and Trump.

"Maybe there has been a misunderstanding. We've said it several times and we repeat it - there has been no decision to hold bilateral talks with the US," said Rouhani.

"In principle, we don't want bilateral talks with the United States," he told parliament at a session convened to approve his picks for two ministerial posts.

"If the United States lifts all sanctions... it would be possible to talk [to them] during 5+1 meetings as in the past," he said, referring to the powers involved in negotiating the 2015 deal.

"We have received several proposals [to have talks with the US] and our answer has always been negative."

Iran has riposted by scaling back its nuclear commitments in response to the US withdrawal from the deal, which gave it the promise of relief from sanctions in return for curbs on its nuclear program.

It has already ramped up its uranium enrichment and stockpiles, and Rouhani said Tuesday a "third step will be enacted in the coming days" unless the remaining parties to the deal honour their own commitments.

"If by Thursday these negotiations yield no results, we will announce the third step of the reduction of our commitments," he said.

On Friday, the International Atomic Energy Agency said just over 10 percent of Iran's uranium stockpile was enriched to 4.5 percent, above the 3.67 percent limit stipulated in the 2015 deal.

The UN watchdog said Iran's total stockpile of uranium, which under the accord should be no more than the equivalent of 300 kilograms of uranium hexafluoride, stood at roughly 360 kilograms.