At least two people have been killed and twelve others injured as a massive explosion ripped through an oil refinery facility in the southern Iranian port city of Abadan.

The incident occurred on Tuesday while Iran's President Mahmoud Ahmadinejad was on sight to inaugurate a new gasoline production unit in the Abadan refinery, Mehr News Agency reported.

Firefighters immediately brought the fire under control, the report added.

A number of the refinery employees suffered gas intoxication after toxic fumes and thick clouds of smoke cast a shadow over the refinery.

Some of those injured or poisoned in the blast were immediately transferred to the Iranian capital of Tehran upon the order of President Ahmadinejad.

A gas leakage in one of the refinery units has been blamed as the cause of the explosion and ensuing fire.

The development plan of Abadan refinery is aimed at producing the premium 94 octane gasoline.