Twenty-seven soldiers have been killed in an explosion at a military base near Iran's capital Tehran, officials say.
The blast occurred when weapons were being moved inside a Revolutionary Guards depot, a spokesman for the elite unit told state TV.
Windows in nearby buildings were shattered and the blast was heard in central Tehran, 40 km (25 miles) away.
Two hours after the explosion a fire still raged and there were traffic jams on nearby roads, a local reporter said.
Local MP Hossein Garousi said "a large part of an ammunition depot exploded," parliament's website reported.
Revolutionary Guards spokesman Ramezan Sharif did not say what had caused the "accident" in the village of Bidganeh, near the city of Karaj.
"Some of the casualties are reported to be in a critical condition," he said.
An emergency worker said that 12 people had been taken to hospital.
Karaj resident Kaveer told the BBC's Newshour programme that the sound was "deafening".
"We were kind of shocked. I just ran out of the house and looked around," he said.
