An  explosion hit the base in Bid Ganeh, near the town of Malard on the western outskirts of Tehran, some 20 kilometres (12 miles) west of the city centre, according to media reports.

"The number of martyrs in today's explosion in one of our ammunition depots stands at 15," commander Ramezan Sharif , a spokesman for the elite unit told state television.

The explosion, which was originally reported as in a gas distribution station, hit "a military base" west of Tehran, Alireza Jane, responsible for security issues in the Tehran's governor office, told the ISNA news agency.

The blast shattered the windows of residential neighbourhoods in the western suburbs of Tehran, witnesses told AFP. It was heard in the city centre.