US Special Representative for Iran Brian Hook said on Thursday that Washington would retaliate with military force if Iran "attacks" American interests in the Middle East.
"If we are attacked we will respond with military force. We have redeployed our forces in the region. We think that this redeployment has a deterrent effect on possible erroneous calculations of the regime", he said.
Hook also said that the US is waiting for the results of an investigation into alleged attacks on four vessels, including two Saudi oil tankers, off the UAE's coast earlier this month, which have been blamed on Iran by Washington and its allies, before discussing a proper response.
Hook on EU's Mechanism to Bypass US Sanctions on Iran
The US is ready to impose sanctions on the EU's Instrument in Support of Trade Exchanges, or INSTEX, designed to bypass American penalties against Iran, Hook said.
His comments were made just a day after Bloomberg cited a letter penned by the Treasury Department's undersecretary for terrorism and financial intelligence, Sigal Mandelker, as saying that the Trump administration would ban the mechanism from the US financial system if it comes into force.
Bolton Warns Iran Against Making 'Big Mistake'
In a parallel development, White House National Security Adviser John Bolton said on Thursday that it would be a "big mistake" if Iran or "its surrogates attacked" American interests, and that a "quick response" and the dispatch of US military assets in the Persian Gulf served to "deter" Tehran.
Bolton continued by claiming that the Iranian "threat is not over" and added that the United States was not pursuing a policy of regime change in the Islamic Republic.
The national security adviser then blasted Iran for "threatening" Washington and its allies as "unacceptable behaviour" which has to stop if they want to negotiate.
Earlier this month, the US upped the ante by deploying the USS Abraham Lincoln aircraft carrier strike group and a bomber task force to the Gulf to send a “clear and unmistakable message” to Iran. In addition, President Donald Trump has confirmed that the Pentagon will deploy 1,500 more troops to the region.
Tehran, meanwhile, announced that it would partially suspend its commitments under the nuclear deal, having set a 60-day deadline for the five remaining signatories to the deal – Russia, China, the UK, France, and Germany – to ensure that Iranian interests are protected or else the country would resume enriching uranium at higher levels.