Iran could make enough fissile material for one nuclear bomb in “about 12 days”, a top US Defence Department official has said.
It had previously been estimated that it would have taken a year while the 2015 Iran nuclear deal was in effect.
Undersecretary for policy Colin Kahl made the comment to a House of Representatives hearing when pressed by a Republican politician as to why the Biden administration had sought to revive the deal, known as the Joint Comprehensive Plan of Action.
“Because Iran's nuclear progress since we left the JCPOA has been remarkable,” Mr Kahl, the third-ranking official in the department, told politicians.
“Back in 2018, when the previous administration decided to leave the JCPOA, it would have taken Iran about 12 months to produce one bomb's worth of fissile material. Now it would take about 12 days.
“And so I think there is still the view that if you could resolve this issue diplomatically and put constraints back on their nuclear programme, it is better than the other options. But right now, the JCPOA is on ice.”
US officials have repeatedly estimated Iran's breakout time — how long it would take to acquire the fissile material for one bomb if it decided to — as being a few weeks long but none has been as specific as Mr Kahl was.
While Washington says Tehran has grown closer to producing fissile material, it does not believe it has mastered the technology to actually build a bomb.
Under the 2015 deal that Donald Trump, US president at the time, abandoned in 2018, Iran had reined in its nuclear programme in return for relief from economic sanctions.
Mr Trump reimposed US sanctions on Iran, leading Tehran to resume previously banned nuclear work and rekindling US, European and Israeli fears that Iran may seek an atom bomb.
Iran denies any such ambition.
The Biden administration has tried but failed to revive the pact over the past two years.
Germany on Wednesday said it was watching Iran’s increasing military build-up with concern, not least because of Tehran’s destabilising activities in the region and drone deliveries to Russia.
The German Foreign Ministry in a statement cited uranium enrichment in Fordow and the brutal repression of Iran’s own population as other reasons for concern.
It said that Germany was in close dialogue with partners in the region and within Europe as well as the United States on these developments.
Meanwhile, Iran has expelled two German diplomats over Germany's "irresponsible interference" in Iran's affairs, Foreign Ministry spokesman Nasser Kanaani said on Wednesday.
"The two German diplomats are being expelled due to their country's irresponsible interference in Iran's internal and judicial affairs," Mr Kanaani said.
In response, the German Foreign Ministry said the move was expected but "is arbitrary and unjustified".
"The staff now being expelled from Iran were working with openness, concern and great commitment despite ever more difficult circumstances. Their expulsion is arbitrary and unjustified, they have done nothing wrong," the ministry added in a statement.
Iran's move on Wednesday follows two employees of the Iranian embassy being ordered to leave Germany on February 22 in protest of Iran's sentencing of a dual-German citizen to death.
Jamshid Sharmahd, an Iranian-German, was sentenced to death by a court in Tehran after being found guilty of planning and directing terrorist acts.
Mr Sharmahd, who also has US residency, was accused of being the mastermind of the 2008 bombing at a mosque that killed 14 people and wounded more than 200 in Shiraz, southern Iran.
Iran's charge d'affaires was also summoned over the issue. “He was informed that we do not accept the massive violation of the rights of a German citizen,” Foreign Minister Annalena Baerbock said at the time.
