Iranians are bracing for the full force of US sanctions due to hit on Monday as the Trump administration reimposes an embargo on oil, the most stringent set of punitive measures since Washington withdrew from the 2015 landmark nuclear deal, known as Joint Comprehensive Plan of Action.

The new sanctions, which also aim to cut off Iran’s banking sector from the global market, are timed to coincide with the anniversary of the 1979 storming by Iranian revolutionaries of the US embassy in Tehran, when angry students took 52 American diplomats hostage for 444 days.

Iran has remained defiant, saying it is confident it can weather the impacts, and that the US will fail to bring down Iranian oil imports to zero. But ordinary people, wary of the fluctuations of the currency and the rising prices of goods, are anxious.

On Sunday, a state-organised rally took place in front of the former US embassy compound in central Tehran to mark the anniversary. The crowd held placards reading “Down with USA”, and “Down with Israel”, while others set US and Israeli flags on fire.

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“Never threaten the Iranian people,” Mohammad Ali Jafari, the commander of Iran’s elite revolutionary guards told people gathering in front of the former embassy, officially referred to as a “den of spies”. “Do not make military threats against us, and do not frighten us with military threats,” he added.

The US president, Donald Trump, announced the reimposition of sanctions by tweeting on Friday a photograph of himself in the style of an advertisement for the Game of Thrones fantasy TV series, with the tagline: “Sanctions Are Coming, November 5”. The office of Iran’s Quds force commander, Qassem Soleimani, retaliated by posting a photo of himself in a similar style alongside the tagline: “I will stand against you.”

Facebook Twitter Pinterest People protesting against the US sanctions, marking the 39th anniversary of the occupation of the former US embassy building in Tehran. Photograph: Fatemeh Bahrami/Anadolu Agency/Getty Images

Inside Iran, however, people are on tenterhooks. Economic grievances were a trigger for a wave of nationwide protests in recent months over the scarcity of the US dollar, unpaid wages and rising prices.

“Nov 5th isn’t the most pivotal moment in this saga,” said Ali Vaez, Iran project director at the International Crisis Group. “Paradoxically, if sanctions prove as effective as the White House is hoping for, they are bound to push Iran to either revive its nuclear program or become more aggressive in the region. Both will significantly increase the risks of a military confrontation.”

Iran is relying on European support. The EU has set up a mechanism – known as a special purpose vehicle (SPV) – to sidestep US sanctions and persuade an increasingly reluctant Iran to stay inside the deal in the hope of rescuing its economy.

Iran’s supreme leader, Ayatollah Ali Khamenei, reacting to Trump’s threats on Saturday, said America’s power was in decline. “The US’s goal in imposing sanctions is to paralyse and prevent the growth of national economy; but it resulted in a movement towards self-sufficiency in Iran,” he said.

Worries about the impacts of the new blanket sanctions are particularly high among Iran’s health sector. Ahmad Ghavideh, the head of Iran’s haemophilia society, said the lives of at least 12,000 patients with bleeding disorders in Iran will be put at immediate risk when the country’s supply of medicine runs out.

Facebook Twitter Pinterest An Iranian man shows his hand painted with Iran’s national flag colours during the anti-US demonstration. Photograph: Abedin Taherkenareh/EPA

“We believe that sanctions are in fact worse than waging a classic war, because when you’re in the war situation at least civilian buildings, and targets are supposed to be spared, while with sanctions in this scale, a whole nation has been targeted,” he said.

A group of respected Iranian mental health professionals signed a letter saying that Iranian people’s access to life-saving medication and medical supplies is getting “seriously jeopardised”.

“Given the indirect toll on human wellbeing, economic sanctions can hence be regarded as a sugarcoated but full-fledged war with the caveat that people die not because of bombs and bullets, but rather as a result of a reduction in access to health care,” they wrote.

“Ordinary Iranian people are the ones who are most seriously suffering from the crippling US-imposed sanctions, which has created a grave burden on their sense of wellbeing and mental health.”

An Iranian student at the Leiden University in the Netherlands said the future of his education was at risk because he relied on his family for his education costs.

“It has been two months since I have come to the Netherlands, but sadly over these last couple of months the value of our currency has seen a [huge] decline or more. I have to pay £16,800 to the university, I paid the first instalment a month ago but still have £13,000 left to pay and I can’t because of the currency depreciation,” he said. “This has really affected me psychologically.”