A massive explosion hit a Revolutionary Guards base in the west of the Iranian capital on Saturday, killing 15 people, a spokesman for the elite unit told state television.
"The number of martyrs in today's explosion in one of our ammunition depots stands at 15," commander Ramezan Sharif was quoted as saying.
He did not disclose how many people were injured in the blast but said some were in ‘critical condition.’
An emergency official, Majid Khaled, quoted by the ISNA news agency, said so far 10 people had been taken to nearby hospitals.
The explosion shortly after 1pm (0930 GMT) hit the base in Bid Ganeh, near the town of Malard on the outskirts of Teheran, some 20km west of the city centre, according to media reports.
"Initial investigations show the blast occurred as ammunition was being moved," Sharif added.
Hossein Garousi, a lawmaker from the area, ruled out the blast being the result of "an act of sabotage or in any way political." He told parliament's website the blast had destroyed ‘a large part of the ammunition depot.’
The explosion shattered the windows of residential neighbourhoods in the western suburbs of Tehran, witnesses said. It was heard in the city centre.
A helicopter and ambulances have been dispatched to the scene, ISNA quoted an official at Teheran's medical emergency centre, Hassan Abbasi, as saying.
Earlier, a Mehr news agency reporter said two hours after the blast, the fire was still raging, and that there were huge traffic jams on roads leading to the base.
In October 2010, a blast at a Guards ammunition storage in the western city of Khorramabad killed 18 of its members and left dozens injured.
Set up after the Islamic revolution of 1979 to defend it against internal and external threats, the Guards have emerged as a powerful military and economic force in Iran in recent years.