Iran's threat of a 'faster, heavier and more painful' retaliation came after US forces said they struck three Iranian oil tankers in the Gulf of Oman, permanently disabling two and destroying a third, in one of the most serious recent confrontations between Washington and Tehran at sea.
Iran has declared the era of 'proportionate responses' over, with parliament speaker Mohammad Bagher Ghalibaf warning that any further attack on the country's interests or security would draw a 'faster, heavier and more painful' response.
