Iran will never pursue a nuclear weapon, its foreign minister has claimed, saying Islam prevented the country from doing so.

Iran has previously said it is ideologically opposed to acquiring nuclear weapons and seeks nuclear power only for civilian purposes. But in the current unpredictable climate it is possible Donald Trump could pick up Javad Zarif’s remarks as a signal to talk.

The White House is pursuing a twin-track strategy of seeking talks while trying to throttle the Iranian economy through sanctions that block trade with Europe and oil sales, and freeze the assets of political and diplomatic leaders.

Iran has said it will breach the uranium enrichment limits set out in the 2015 nuclear deal on Thursday, but that does not imply the country is on the path to building a nuclear weapon.

Q&A What is the Iran nuclear deal? Show Hide In July 2015, Iran and a six-nation negotiating group reached a landmark agreement known as the Joint Comprehensive Plan of Action that ended a 12-year deadlock over Tehran’s nuclear programme. The deal, struck in Vienna after nearly two years of intensive talks, limited the Iranian programme, to reassure the rest of the world that it cannot develop nuclear weapons, in return for sanctions relief.

At its core, the JCPOA is a straightforward bargain: Iran’s acceptance of strict limits on its nuclear programme in return for an escape from the sanctions that grew up around its economy over a decade prior to the accord. Under the deal, Iran unplugged two-thirds of its centrifuges, shipped out 98% of its enriched uranium and filled its plutonium production reactor with concrete. Tehran also accepted extensive monitoring by the International Atomic Energy Agency (IAEA), which has verified 10 times since the agreement, and as recently as February, that Tehran has complied with its terms. In return, all nuclear-related sanctions were lifted in January 2016, reconnecting Iran to global markets. The six major powers involved in the nuclear talks with Iran were in a group known as the P5+1: the UN security council’s five permanent members – China, France, Russia, the UK and the US – and Germany. The nuclear deal is also enshrined in a UN security council resolution that incorporated it into international law. The 15 members of the council at the time unanimously endorsed the agreement. On 8 May 2018, US president Donald Trump pulled his country out of the deal. Iran announced its partial withdrawal from the nuclear deal a year later. Saeed Kamali Dehghan, Iran correspondent

Zarif pointed to the past use of nuclear weapons by the US and to recent comments by Trump that he had called off a military strike on Iran because it would have killed 150 people.

“You were really worried about 150 people? How many people have you killed with a nuclear weapon? How many generations have you wiped out with these weapons?” Zarif said on Tuesday.

“It is us who, because of our religious views, will never pursue a nuclear weapon.”

The US president again threatened Iran with “obliteration” in a Twitter tirade in which he also accused the country’s leaders of killing 2,000 Americans.

“The Iranian leadership doesn’t understand the words ‘nice’ or ‘compassion’, they never have. Sadly, the thing they do understand is strength and power, and the USA is by far the most powerful military force in the world, with $1.5tn invested over the last two years alone,” he wrote.

“The US has not forgotten Iran’s use of IEDs & EFPs (bombs), which killed 2,000 Americans, and wounded many more … Any attack by Iran on anything American will be met with great and overwhelming force. In some areas, overwhelming will mean obliteration.”

The angry tweets came after Iran said the US’s decision to impose sanctions on its supreme leader and other top officials was “idiotic” and had permanently closed the path to diplomacy between Tehran and Washington.

Trump imposed fresh sanctions on Monday against the supreme leader, Ayatollah Ali Khamenei, and military chiefs, in an unprecedented step designed to increase pressure on Iran after Tehran’s downing of an unmanned American drone. Khamenei is Iran’s utmost authority, who has the last say on all state matters.

Washington said it would also impose sanctions this week on Zarif, who negotiated the 2015 nuclear deal with the US and other major powers and has spearheaded Iranian diplomacy since.

Iran’s president, Hassan Rouhani, described the White House as “afflicted by a mental disability” and said the sanctions against Khamenei were “outrageous and idiotic”, especially as the 80-year-old cleric has no overseas assets and no plans to ever travel to the US.

Tehran said the US had spent weeks demanding that Iran match America’s diplomacy with its own diplomacy, rather than military responses, but was now trying to immobilise its chief diplomat.

“Imposing useless sanctions on Iran’s supreme leader and the commander of Iran’s diplomacy is the permanent closure of the path of diplomacy,” the foreign ministry spokesman Abbas Mousavi said in a tweet on Tuesday. “Trump’s desperate administration is destroying the established international mechanisms for maintaining world peace and security.”

Speaking in Israel, Trump’s national security adviser, John Bolton, insisted the president remained open to real negotiations and “all that Iran needs to do is walk through that open door”.

Iran’s decision to breach the nuclear deal is a response to US sanctions and Europe’s failure to provide economic protection. It is due to be followed by more serious breaches on 7 July.

This places the EU in a dilemma since France, Germany and the UK are desperate to keep the deal alive but cannot find a route to de-escalate the crisis between Tehran and Washington.

The three European countries issued a statement on the margins of the UN security council on Monday urging Iran to stay inside the deal, saying: “It is in everyone’s interest to show restraint and avoid any actions that would undermine this vital pillar of the non-proliferation regime and of our collective security.”

They also insisted they were working hard to implement their commitments to Iran – a reference to setting up financial mechanisms to help Tehran trade with Europe without the threat of US sanctions – and condemned recent attacks on oil tankers in the Gulf of Oman.

The UK foreign secretary, Jeremy Hunt, warned Iran not to breach the uranium enrichment limits, saying in the Commons: “It is absolutely essential they stick to that deal in its entirety for it to preserve and for us to have a nuclear-free Middle East.”

He also ruled out British involvement in military action. “The US is our closest ally. We talk to them the whole time but I cannot envisage any situation where they request, or we agree to, any moves to go to war.”

He again called for de-escalation, saying: “Neither side wants war, but it is very important for there to be ladders for people to climb down so discussions can take place.”

Trump is due to raise the issue of tightening maritime security in the Gulf at a G20 summit starting on Friday in Japan. He wants Asian countries including Korea and Japan to contribute more to defence of shipping in the Gulf especially the strait of Hormuz.

Analysts said the impact of the fresh US sanctions on an already heavily sanctioned country would be limited. “The newly announced Iran sanctions are symbolic,” said Jarrett Blanc, a former senior state department official now at the Carnegie Endowment for International Peace.

Trump said he was willing to pursue dialogue with Tehran without preconditions, but the sanctions appeared to make such talks even less likely.

Trump says he stopped airstrike on Iran because 150 would have died Read more

The Iranian ambassador to the UN, Majid Takht-Ravanchi, said: “No one in clear mind can have a dialogue with somebody who is threatening you with sanctions; as long as that is still there, there is no way we can have a dialogue.”

The ratcheting up of tensions between the two countries comes in the wake of the Gulf of Oman tanker attacks, when two vessels were damaged by explosions. The Trump administration blamed Iran for the attacks, but Tehran denied responsibility.

Then last week a US drone was shot down by Iran, further escalating the crisis. The US president responded by ordering an attack on Iran, before pulling back and opting for stronger sanctions instead.

Tensions with Iran have been mounting since Trump withdrew the US from the 2015 nuclear deal last year and began applying pressure on Tehran through economic sanctions.