BBC diplomatic correspondent

Almost a decade since the world powers have sealed a historic agreement to limit the Iranian nuclear program, it is a moment of crisis for Iran and the international community.
The country is now closer than ever to be able to make a nuclear bomb.
And the agreement – designed to prevent Iran from developing a nuclear weapon – expires later this year.
“It’s a real fork at the time of the road,” said Dr. Sanam Vakil of the London Chatham House reflection group. “Without a significant and successful diplomacy, we could see the Iranian weapons where we could see a military strike against the Islamic Republic.”
The agreement, meticulously negotiated over almost two years, under the chairmanship of Barack Obama, imposed restrictions on Iranian nuclear activities in exchange for sanctions which paralyzed the country’s economy.
But after Donald Trump withdrew from the agreement in 2018 during his first presidency and restored the American sanctions, Iran gradually ceased to comply with his commitments.
It accelerated its enrichment of uranium – used to make reactor fuel but also potentially nuclear bombs – to close the quality of weapons.
Experts say that Iran would now take less than a week to enrich enough equipment to make a single nuclear weapon.
Hence a wave of urgent diplomatic activities by the United States and the other five parties to the agreement-the United Kingdom, China, France, Germany and Russia.

A closed -door meeting of the United Nations Security Council discussed the Iranian nuclear program on Wednesday.
And China organizes talks with Iran and Russia on Friday in search of a “diplomatic” resolution.
“In the current situation, we believe that all parties should maintain calm and restraint to avoid climbing the Iranian nuclear situation, or even walking towards confrontation and conflicts,” the Chinese Foreign Ministry spokesman Mao Ning said.
On Wednesday, a letter from President Trump was given to Tehran by a main diplomat of the United Arab Emirates.
The content has not been made public.
But President Trump, after having imposed new sanctions on Iran as part of a “maximum pressure” campaign, expressed a televised ultimatum to Iran last week: to conclude an agreement or other.
“I wrote a letter saying to them:” I hope you will negotiate because if we have to go militarily, it’s going to be a terrible thing “,” he said.
The supreme leader of Iran, Ayatollah Ali Khamenei, seemed to reject the idea of talks with “intimidation”.
Similarly – publicly – President Masoud Pezeshkian, who had previously supported a resurrection of the nuclear agreement, in exchange for the end of the sanctions.
But the country has sent mixed messages.
“There are camps inside the country that promote negotiations,” said Dr. Vakil. “And there are camps that see the weapon as the best opportunity for Iran to manage its safety.”
Confidence in the Trump administration is very failed.
“They saw his erratic and very intimidating approach [Ukraine’s President Volodymyr] Zelensky. And his bizarre proposals on Gaza and they don’t want to be put in this position, “adds Dr. Vakil.
Iran hates the humiliation of having a pistol held in the head. But it is currently vulnerable – weakened militarily by Israeli air strikes last year, which would have destroyed most of the aerial defenses protecting its nuclear program.
Israel had long wanted to remove the facilities.
Iranian authorities continue to emphasize that the country’s nuclear program is for peaceful purposes.
But the concern in the international community becomes more and more acute.

The International Atomic Energy Agency (IAEA) – responsible for monitoring the Moribund nuclear agreement – said that it has seen Iran strengthen its nuclear capacities in various facilities across the country in recent years.
According to the director general Rafael Rafael Rafael Rafael Rafael Rafael Grossi, his uranium stock enriched up to 60% – almost 90% required for a weapon – increases very, very quickly “.
“The significantly increased production and accumulation of high uranium enriched by Iran, the only non -nuclear weapon state to produce such nuclear materials, is very worrying,” IAEA said in its latest report.
But the nuclear guard dog is no longer able to verify exactly what Iran does, because the authorities have deleted the IEA monitoring equipment.
Mr. Grossi says that diplomatic engagement with Iran – through possible channels – is now urgent and “essential”.
On October 18, the parties to the 2015 nuclear agreement will lose the capacity to impose so-called “snap-back” sanctions on Iran for having violated its conditions.
Thus, the United Kingdom, France and Germany now exercise the threat of snap-back sanctions, in the hope of putting pressure when they can still.
“We are clear that we will take all diplomatic measures to prevent Iran from acquiring a nuclear weapon, which includes the use of Snapback, if necessary,” the British United Nations Assistant, James Kariuki said on Wednesday.
The issues are raised for Iran – and the world.
“If Tehran decides to build a bomb, he could enrich enough uranium for several warheads in a few weeks,” according to Dr. Alexander Bollfrass, who focuses on the prevention of nuclear proliferation for the International Institute for Strategic Studies, another London -based reflection group.
The design and assembly of a deliverable weapon would however take several months to a year or more, he told the BBC.
“Iran is closer than ever to the ability of nuclear weapons,” he said. “But it is still not clear if he has decided to develop nuclear weapons or if he is looking for a negotiation lever effect.”