Blast at Revolutionary Guards base near Tehran, reports about Israeli involvement

 Smoke rises up from the explosion at a Revolutionary Guard ammunition depot and storage facility for long range missiles outside Bidganeh, some 40 kilometers west of Tehran.  (AP)

 Update:
While Iranian officials insist the explosion at the Bidganeh base was accidental, caused by the movement of ammunition, claims from anonymous western and Israeli officials that Saturday's blast was a covert Israeli operation have gained momentum.
Leading Israeli daily Yediot Ahronot picked up a post by US blogger Richard Silverstein claiming the Mossad had teamed up with Iranian militant group Mujahideen e-Khalq (MEK) to execute the alleged attack. MEK denies involvement in the attack.
Leftwing broadsheet Ha'aretz also led with reports that a western intelligence source quoted in Time magazine had claimed the Mossad carried out the attack in an attempt to stall Iran's development of a nuclear weapon. The official is said to have warned: "There are more bullets in the magazine."
The blast at the base, which is reported to have been a storage facility for long-range missiles, was so powerful that it was said to have been felt 30 miles away in the capital, Tehran.
Among those killed was Major General Hassan Moghaddam, the Revolutionary Guard Commander charged with "ensuring self-sufficiency" in armaments, and described by Iranian media as a pioneer in Iranian missile development. (end of update)
 
Seventeen 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. Revolutionary Guards spokesman Ramezan Sharif did not say what had caused the "accident" in the village of Bidganeh, near the city of Karaj.

The death toll was revised down from an earlier figure released by the Revolutionary Guards of 27. An emergency worker said that 12 people had been taken to hospital. "Some of the casualties are reported to be in a critical condition," he said.
Local MP Hossein Garousi said "a large part of an ammunition depot exploded," parliament's website reported. Windows in nearby buildings were shattered and the blast was heard in central Tehran, 40 km  away. Two hours after the explosion a fire still raged and there were traffic jams on nearby roads, a local reporter said. Karaj resident Kaveer told the BBC's News Hour programme that the sound was "deafening".
"We were kind of shocked. I just ran out of the house and looked around," he said.

There have been occasional unexplained explosions in Iran before.
Eighteen people were killed in a blast at a Revolutionary Guards base in Khorramabad in the north-western Lorestan province in October 2010. The latest blast comes at a time of heightened tensions over Iran's nuclear ambitions.