US Secretary of State Mike Pompeo said last month that he triggered a 30-day process at the council leading to the return of UN sanctions on Iran on Saturday evening that would also stop a conventional arms embargo on Tehran from expiring on Oct. 18.

But 13 of the 15 Security Council members say Washington’s move is void because Pompeo used a mechanism agreed under a 2015 nuclear deal between Iran and world powers, which the United States quit in 2018.

“There would appear to be uncertainty whether or not the process … was indeed initiated and concomitantly whether or not the (sanctions) terminations … continue in effect,” Guterres wrote in a letter to the council, seen by Reuters.

“It is not for the Secretary-General to proceed as if no such uncertainty exists,” he said.

UN officials provide administrative and technical support to the Security Council to implement its sanctions regimes and Guterres appoints independent experts to monitor implementation. He said that “pending clarification” of the status of the Iran sanctions, he would not take any action to provide that support.

Washington argues it triggered the return of sanctions – known as “snapback” – because a UN resolution that enshrines the pact still names it as a participant. Diplomats say few countries are likely to reimpose the measures lifted under the 2015 deal, known as the JCPOA.

“If UN Member States fail to fulfill their obligations to implement these sanctions, the United States is prepared to use our domestic authorities to impose consequences for those failures,” Pompeo said in a statement on Saturday.

He said that in the coming days Washington would announce additional measures to strengthen the implementation of the UN sanctions and “hold violators accountable.”

Russia’s Deputy UN Ambassador Dmitry Polyanskiy responded on Twitter, “We all clearly said in August that US claims to trigger snapback are illegitimate. Is Washington deaf?”

Longtime US allies Britain, France and Germany told the council on Friday that UN sanctions relief for Iran would continue and that any decision or action taken to reimpose UN sanctions “would be incapable of legal effect.”

Guterres aims to forestall a new nuclear arms race and get the big powers back into negotiations after two decades of stalemate, according to a Geneva-based expert familiar with the plans, who requested anonymity.

The expert said Guterres also wants to end “state-led paralysis” in talks on cyber warfare and robotics by getting the private sector involved, and to start talks on use of explosives in urban areas and curbing access to conventional weapons, the biggest killer, Reuters reported.

Chances of success are uncertain at best. But with nuclear tensions rising, Guterres may be uniquely placed to oil the wheels of negotiations given a 2009 UN Security Council pledge to “create the conditions for a world without nuclear weapons”.

“If Guterres is clever he can use that to say: ‘Okay what have you done in the past 10 years?'” said Marc Finaud, an expert at the Geneva Centre for Security Policy.

But a US official, speaking on condition of anonymity, told Reuters that nuclear disarmament was an “aspirational goal” only, and it was hard to conceive of it in the near term.

“We don’t believe that it’s time for bold initiatives, particularly in the area of nuclear weapons,” the official said, adding Guterres should also tread carefully in new technologies such as killer robots, known as “autonomous” weapons.

“I worry that the Secretary-General may be trying to treat the symptoms and not the root causes of why countries arm and rearm.”

The US Nuclear Posture Review, published on Friday, aims to improve deterrence, ensuring Russia, China, North Korea and Iran cannot mistake the US willingness to defend itself, the official added.

The US official said the problem was political will and the fact Russia – with whom tensions have risen over issues ranging from Russian involvement in Ukraine’s conflict to alleged Russian interference in the 2016 US election campaign – was not a willing or trusted negotiating partner.

“We have to let them (Russia) know that we are dealing with them from a position of strength. Over the last eight years there’s been a perception of weakness. We want to disabuse them of that notion.”

Guterres’ strategy, to be spearheaded by his disarmament chief Izumi Nakamitsu, seeks to revive talks across the spectrum despite deepening US-Russian mistrust and heightened tensions on the divided Korean peninsula.

“The path to peace through disarmament does not lie waiting for the right security situation to materialize, while countries increase their military budgets and stockpiles year after year,” she said in a speech last October.

“We should not shy away from bolder thinking.”

The US official said the negotiating forum was “littered” with stalled initiatives aiming to think outside the box.

They include China and Russia’s thrust for a treaty on weapons in space and Russia’s hope for a treaty to stop Islamist militants obtaining weapons of mass destruction.

Nakamitsu is expected to invite key officials, including diplomats from the United Nations’ five veto-wielding powers, including Washington and Moscow, to a retreat near New York later this month for discussions.

Guterres hopes to unveil his initiative in Geneva at the end of February, when foreign ministers, including Sergei Lavrov of Russia, are expected at the UN Human Rights Council and the Conference on Disarmament, before a full launch in April.

Richard Lennane, head of the non-profit Geneva Disarmament Platform, said it was the right time for what appeared to be an unprecedented and ambitious move, and encouraging that Guterres was launching it early in his tenure.

“The tensions between Donald Trump and the North Korean leader have frightened a lot of people, and for the first time in a long time people have realized that there’s an imminent prospect of a nuclear war starting. So I think that is fertile ground to try an initiative like this,” he said.

Hariri, a protege of Riyadh, on Saturday announced his surprise resignation in a broadcast from the Saudi capital. He said he feared for his life.

“The secretary-general is concerned by news of the offer of resignation of Lebanon Prime Minister Saad Hariri,” Guterres spokesman Stephane Dujarric said in a statement, AFP reported.

“He hopes all sides will focus their efforts on supporting the continuity of Lebanon’s State institutions, in adherence with the constitution and safeguarding the country’s security and stability,” he added.

“The United Nations remains committed to supporting the security, sovereignty and territorial integrity of Lebanon.”