Former Mujahedin-e Khalq spokesman Alireza Jafarzadeh, citing what he called reliable sources inside Iran, said that the explosion hit the Modarres Garrison of the Islamic Revolutionary Guard Corps west of Tehran. The group, also known as the MEK, has in the past disclosed the sites of several key Iranian nuclear installations as well as details of their operations.
Jafarzadeh, now an author and commentator critical of Tehran's clerical regime, said the Modarres Garrison belongs to the IGRC's missile unit and the blasts "resulted from the explosion of IRGC missiles." He did not say what triggered the explosion.
The blast comes just days after a new report by the U.N.'s nuclear watchdog agency that Iran is conducting nuclear weapons-related research and follows unconfirmed reports that Israel was considering a military strike on Tehran's nuclear program.
Iranian officials said the blast was accidental and happened when soldiers were moving ammunition at a depot west of Tehran. Officials said 17 soldiers were killed.
Iran's gas pipelines and military installations have been hit by several mysterious blasts in recent years, and Tehran has accused the West of engaging in a campaign of sabotage and assassination against the regime. But an Iranian lawmaker Saturday ruled out sabotage at the blast site.