Iran rules out direct US talks
His comments were followed by the U.S. imposing sanctions on Iran's space programme, as Washington claimed a recent explosion on a launch pad was a sign of missile work.
Iran and three European countries -- Britain, France and Germany -- have been trying to save a landmark agreement reached in 2015 and meant to limit Tehran's nuclear programme after the U.S. pulled out last year.
But French Foreign Minister Jean-Yves Le Drian cautioned that several issues were still hindering their efforts.
"There is still lots to work out. It's still very fragile," Le Drian told journalists in Paris on Sept. 3.
France has been leading efforts for dialogue, with President Emmanuel Macron expressing hope during G7 talks in late Septust of organising a meeting between Rouhani and U.S. President Donald Trump.
However, in a speech to Iran's parliament on Sept. 3, Rouhani said any dialogue with the U.S. would have to fall within the framework of the six major powers that agreed the nuclear deal.
"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 U.S.," said the Iranian president.
"In principle, we don't want bilateral talks with the United States," he told lawmakers, saying Tehran had rebuffed several proposals for such talks.
"If the United States lifts all sanctions... it would be possible to talk (to them) during 5+1 meetings as in the past," Rouhani said, referring to the powers involved in negotiating the 2015 deal.
Tehran and Washington have been at loggerheads since May 2018 when Trump unilaterally withdrew the U.S. from the nuclear deal and began reimposing crippling sanctions.
The arch-foes were on the cusp of confrontation in June when Iran downed a U.S. drone and Trump ordered retaliatory strikes before cancelling them at the last minute.
On Sept. 3, U.S. Secretary of State Mike Pompeo said that the US was imposing sanctions on the Iran Space Agency and two affiliated research centres, in order to constrain its ballistic missile capabilities.
The move came after an explosion at an Iranian satellite launch pad on August 29, which Pompeo alleged was an "attempt to launch a space launch vehicle".
"The United States will not allow Iran to use its space launch program as cover to advance its ballistic missile programs," he added.
In response to the U.S. withdrawal from the nuclear deal, Iran has scaled back its nuclear commitments.
The 2015 deal had given it the promise of relief from sanctions in return for curbs on its atomic programme.
It has already increased its uranium enrichment and stockpiles, and Rouhani said on Sept. 3 a "third step will be enacted in the coming days" unless the remaining parties to the deal honour their own commitments.
Reacting to the threat, a French diplomat involved in talks with Tehran said any further violation of the deal would send a "bad signal".
The diplomat, who spoke on condition of anonymity, said such a move would "make the (mediation) work more complicated", but said France would remain engaged with Tehran to try promote dialogue.
On Aug. 30, 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 (661 pounds) of uranium hexafluoride, stood at roughly 360 kilograms.
But Rouhani stressed the Iranian countermeasures were reversible.
"Our steps have been taken in such a way that it doesn't take much time to get back to the starting point," he said.
He also voiced regret over the failure of European governments to fulfil pledges they made during negotiations.
"Europeans haven't acted on their commitments or couldn't... in some cases they could have acted but did not," he said.
"What we are asking of the other countries is that they continue to buy our oil.
"We can continue negotiations even after the third step," he added.
Rouhani has had a series of phone calls with Macron in recent weeks aimed at salvaging the nuclear deal.
The French president has been trying to convince the U.S. to offer Iran relief from sanctions it has imposed on the Islamic republic since pulling out of the agreement.
The 2015 deal was brokered between Iran and the so-called 5+1 -- UN Security Council permanent members Britain, China, France, Russia and the United States plus Germany.