The leader of Iran's Revolutionary Guard has ordered his forces to potentially target the US Navy after President Donald Trump's tweet threatening to sink Iranian vessels.
Iran on Thursday separately summoned the Swiss ambassador, who looks out for America's interests in the country, to complain about Trump's threat coming amid months of escalating attacks between the two countries.
While the coronavirus pandemic temporarily paused those tensions, Iran has since begun pushing back against the Trump administration's maximum pressure policy both militarily and diplomatically.
Speaking to state television Thursday, Guard General Hossein Salami warned his forces "will answer any action by a decisive, effective and quick counteraction".
"We have ordered our naval units at sea that if any warships or military units from the naval force of America's terrorist army wants to jeopardise our commercial vessels or our combat vessels, they must target those (American) warships or naval units," Salami said.
The latest dispute comes after the US Navy said last week that 11 Guard naval gunboats had carried out "dangerous and harassing approaches" to American Navy and Coast Guard vessels in the Persian Gulf.
The Americans said they used a variety of nonlethal means to warn off the Iranian boats, and they eventually left. Iran, meanwhile, accused the US of sparking the incident, without offering evidence.
Iran has had tense encounters at sea for years with the US Navy in the Persian Gulf and the Strait of Hormuz, through which 20 per cent of all oil passes. The US has patrolled the area to protect global shipping for decades, something Iran describes as akin to it patrolling the Gulf of Mexico.
Trump on Wednesday, facing a collapsing global energy market and the pandemic at home amid his re-election campaign, tweeted out a warning to Iran that he ordered the Navy to "shoot down and destroy any and all Iranian gunboats if they harass our ships at sea".
"We don't want their gunboats surrounding our boats, and travelling around our boats and having a good time," Trump told reporters on Wednesday at the White House.
"We're not going to stand for it. ... They'll shoot them out of the water."
The International Crisis Group, noting the tensions, urged both countries to create a hotline to avoid a possible military confrontation.
Australian Associated Press