US Secretary of State Mike Pompeo on Monday has said his country is imposing the "strongest sanctions in history" on Iran.
In a speech in Washington, America's top diplomat said Iran would be "battling to keep its economy alive" after the sanctions took effect, reports BBC.
He said he would work closely with the Pentagon and regional allies "to deter any Iranian aggression".
Earlier this month, President Donald Trump took the US out of the landmark 2015 Iran nuclear deal.
In his first major foreign policy speech as secretary of state, Mr Pompeo unveiled the administration's "Plan B" for countering the Islamic Republic.
He laid out 12 conditions for any "new deal" with Iran, including the withdrawal of its forces from Syria and an end to its support for rebels in Yemen.
Others include Tehran:
Mr Pompeo said relief from sanctions would only come when Washington had seen a real change in Iran's policies.
"We will apply unprecedented financial pressure on the Iranian regime," he said. "The leaders in Tehran will have no doubt about our seriousness.
"Iran will never again have carte blanche to dominate the Middle East."
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