Secretary of State Mike Pompeo has vowed the United States will “crush” Iran’s influence in the Middle East by imposing the “strongest sanctions in history”.

In a speech delivered in Washington late Monday night, Mr Pompeo warned: “The leaders in Tehran will have no doubt about our seriousness.” 

“These will end up being the strongest sanctions in history by the time we are complete,” he told Washington-based conservative think tank, the Heritage Foundation.

Financial pressure was just one of the measures Mr Pompeo threatened to use to curb the potency of Tehran, two weeks after President Donald Trump canceled US participation in the 2015 Joint Comprehensive Plan of Action (JCPOA) nuclear agreement with Iran.

“We will ensure freedom of navigation on the waters in the region. We will work to prevent and counteract any Iranian malign cyber activity,” the Secretary of State said.

“We will track down Iranian operatives and their Hezbollah proxies operating around the world and crush them,” Mr Pompeo added.

“Iran will never again have carte blanche to dominate the Middle East.”

Mr Pompeo consulted the foreign ministers of Germany, France and Britain, the European participants in the JCPOA, in preparing the Iran policy, the State Department said.

China and Russia are the other countries in the deal. All remaining participants have pledged to stay in the agreement without US support.

Mr Pompeo described the JCPOA as a mistaken gamble.

“The bet that the JCPOA would increase Middle East stability was a bad one for America, for Europe, for the Middle East and indeed for the entire world,” he said.

“It is clear that the JCPOA has not ended Iran’s nuclear ambitions, nor did it deter its quest for regional hegemony.”

US strategy toward Iran “will now be executed outside of the JCPOA,” Mr Pompeo said.

“We’ll continue to work with allies to counter the Iranians’ destabilising activities in the region, block their financing of terror and address Iran’s proliferation of missiles and other advanced weapons systems that threaten peace and stability,” he said.

Mr Pompeo asserted that any new agreement must ensure that Iran has “no path to a nuclear weapon – not now, not ever.”

US sanctions, suspended under the nuclear deal, will be restored over the next five months.

“The Iranian regime should know that this is just the beginning,” Mr Pompeo said.

“Iran will be forced to make a choice: either fight to keep its economy off life support at home, or keep squandering precious wealth on fights abroad. It will not have the resources to do both.”