Iran has reached a moment of truth and must decide in days, not weeks, whether to accept the text of a nuclear deal accepted by China, Russia, European powers and the US, the French foreign minister, Jean-Yves Le Drian, has said.

His claim that the text was now agreed, not just between western powers, but also Russia and China, is designed to put maximum pressure on Iran to accept the attempt to revive its landmark nuclear deal, by which it agreed to limit nuclear activity in return for the lifting of some sanctions.

Tehran’s negotiators have been holding out in recent weeks for the wider lifting of US economic sanctions and some form of political statement by the US Congress that it will not walk away from the deal as it did in 2018, only three years after it came into force.

“We have arrived at the hour of truth. It is not a question of weeks, it is a question of days. We have arrived at a point of sufficient convergence with the other countries, the accord is within reach,” Le Drian told the French Sénat on Wednesday.

“They (Iran) have a very clear choice, either they unleash a serious crisis in the next few days … or they accept an agreement that respects the interests of all the parties.”

Later on Wednesday, Iran’s lead negotiator tweeted: “After weeks of intensive talks, we are closer than ever to an agreement; nothing is agreed until everything is agreed, though.

“Our negotiating partners need to be realistic, avoid intransigence and heed lessons of past 4yrs. Time for their serious decisions.”

Earlier in the day, the Élysée issued a statement saying the French president, Emmanuel Macron, and his Chinese counterpart, Xi Jinping, had spoken by phone and agreed that, “Iran must fully comply with its nuclear responsibilities”.

Wang Qun, the head of the Chinese delegation in Vienna, where the talks now in their eighth round have been taking place, told reporters: “We are in the final stages of negotiations. I hope that the [final] steps will be taken towards each other, because we are one step closer to the final agreement.”

The Russian ambassador to the Vienna talks, Mikhail Ulyanov, simply said non-stop talks were under way.

Neither ambassador’s remarks quite tallied with claims that Russia and China had endorsed the text of the accord, and the claims that the talks have only days left may be construed by Iran as another attempt to force them to accept the deal.

But the Iranian foreign minister, Hossein Amir-Abdollahian, in an interview in the Financial Times, said the Iranian public could not simply accept a statement from the US president that he did not intend to leave the deal, something Joe Biden has already formally said.

The 2015 deal began to unravel in 2018 when Donald Trump withdrew the US and reimposed sanctions on Iran, which then began breaching the accord’s limits on its uranium enrichment.

Amir-Abdollahian said the US Congress and perhaps other parliaments should issue a political statement on Washington’s commitments to the UN security council and return to the nuclear deal. “At least their parliamentarians or their parliamentary speakers, including the US Congress, make a political statement announcing their commitment to the agreement and returning to implementation,” he said.

Such a statement would not have any legal force, but has symbolic value for Iran as it tries to sell the deal internally. Resistance to the deal inside the US Republican party is, however, deep.

Referring to the lifting of sanctions, Amir-Abdollahian said: “Iran wants these talks to lead to the complete lifting of sanctions.” But the Biden administration only wants to lift the economic sanctions that were “imposed” on Iran during the Trump era, calling the difference between the two sides “a challenge.”