Iran will destroy U.S. warships if Tehran's security is threatened in the Gulf, head of Iran's elite Revolutionary Guards Hossein Salami told state TV on Thursday, a day after U.S. President Donald Trump warned Tehran over "harassment" of U.S. ships."I have ordered our naval forces to destroy any American terrorist force in the Persian Gulf that threatens security of Iran's military or non-military ships," Salami told state TV.

"Security of the Persian Gulf is part of Iran's strategic priorities."

Trump said on Wednesday he had instructed the U.S. Navy to fire on any Iranian ships that harass it at sea, but said later he was not changing the military’s rules of engagement.