Any Iranian move to blockade the Strait of Hormuz would be considered as an 'act of war', a top US military official said yesterday.

Iran would 'not be allowed' to take control of the key oil route and an attempt to do so would provoke a 'vigorous' international response, outgoing Fifth Fleet Commander Vice-Admiral Kevin Cosgriff was quoted as saying by the Gulf Daily News, our sister newspaper.

He was responding to Iranian Revolutionary Guard commander General Mohammed Ali Jafari's warning on Saturday that Iran would choke off the strait if the country was attacked.

A quarter of the world's oil supplies pass through the narrow stretch, between the Gulf of Oman and the Arabian Gulf.

'I cannot imagine, given the critical nature of that body of water, that the international community would not be outraged should Iran or any entity move to restrict the freedom of navigation,' Vice-Adm Cosgriff told a Press conference at the US navy base in Juffair.

'They are not going to be allowed to do so. It would be an act of war. In a tight oil market, the international community would respond vigorously to that.' He would not specify what action the US would take.