US President Donald Trump has launched an extraordinary threat at Iran in a furious tweet declaring “you will suffer consequences the likes of which few have ever suffered before”.

His outburst comes after Iranian President Hassan Rouhani cautioned Mr Trump about pursuing hostile policies against Iran’s capital of Tehran, saying “America should know … war with Iran is the mother of all wars.”

Secretary of State Mike Pompeo said at the weekend that the US was not afraid to sanction top-ranking leaders of the “nightmare” Iranian regime, pursuing a strategy aimed at Iranian compliance with stringent US demands.

Following Washington’s pullout from the Iran nuclear accord that stunned Washington’s closest European allies, Pompeo on May 21 unveiled the “new strategy” to force Iran’s submission to a dozen demands.

“We weren’t afraid to tackle the regime at its highest level,” Pompeo said in a speech to the Iranian diaspora in California, referring to sanctions levelled in January against Sadeq Larijani, the head of Iran’s judiciary, for human rights violations.

Pompeo also confirmed that Washington wants all countries to reduce their imports of Iranian oil “as close to zero as possible” by November 4, or face American sanctions.

“There’s more to come,” Pompeo said of the US financial penalties.

Mr Trump on May 8 decided to restore all the sanctions that had been lifted as part of a multinational agreement, signed on to by former president Barack Obama’s administration in exchange for curbs on Iran’s nuclear program.

The 2015 agreement was in response to fears that Iran was developing a nuclear bomb.