US President Donald Trump warned the world Tuesday against doing business with Iran as Washington reimposed “the most biting sanctions ever” on the Islamic republic, triggering a mix of anger, fear and defiance in Tehran.

Trump’s May withdrawal from a landmark 2015 nuclear deal with Tehran had spooked investors and triggered a run on the Iranian rial long before the punishing sanctions went back into force.

The newly reimposed sanctions, which target access to US banknotes and key industries such as cars and carpets, were unlikely to cause immediate economic turmoil.

Iran’s markets were actually relatively buoyant, with the rial strengthening by 20 percent since Sunday after the government relaxed foreign exchange rules and allowed unlimited, tax-free gold and currency imports.

But the second tranche of sanctions, which kicks in on November 5 and targets Iran’s vital oil sector, could be far more damaging – even if several key customers such as China, India and Turkey have refused to significantly cut their purchases.

“The Iran sanctions have officially been cast. These are the most biting sanctions ever imposed, and in November they ratchet up to yet another level,” Trump wrote on Twitter.

“Anyone doing business with Iran will NOT be doing business with the United States. I am asking for WORLD PEACE, nothing less.”

European governments – who signed the Iran nuclear deal along with Washington – are infuriated by Trump’s strategy that has prompted many of their large firms to leave Iran for fear of US penalties.

Within hours of the sanctions taking effect, German carmaker Daimler said it had “suspended our already limited activities in Iran in accordance with the applicable sanctions.”

Trump said Monday that he was open to new talks to reach a “more comprehensive deal” with Iran.

“We want to see a much broader retreat by Iran from their support for international terrorism, their belligerent military activity in the Middle East and their ballistic missile, nuclear-related programs,” National Security Advisor John Bolton told Fox News.

“There’s a lot going on here that Iran needs to be held accountable for.”

But Iranian President Hassan Rouhani has dismissed the idea of talks while sanctions are in effect, and accused America of waging “psychological warfare.”

In Tehran, residents were on edge.

“I feel like my life is being destroyed,” said one construction worker on the streets of the capital. “I can’t afford to buy food, pay the rent.”

‘Not got this right’

The return of US sanctions left some of Washington’s partners unimpressed.

British Foreign Office Minister Alastair Burt said that the “Americans have really not got this right.”

The nuclear deal was important “not only to the region’s security but the world’s security,” he told the BBC.

Russia’s foreign ministry said it was “deeply disappointed” by the return of sanctions, adding that it would do “everything necessary” to save the 2015 nuclear deal.

Iranian Foreign Minister Mohammad Javad Zarif told reporters that the global reaction to Trump’s move showed that the US was diplomatically isolated.