Explosion came from hidden missile production site

DUBAI, United Arab Emirates — An explosion that rattled Iran’s capital came from an area in its eastern mountains that analysts believe hides an underground tunnel system and missile production sites, satellite photographs showed Saturday.

What exploded in the incident early Friday that sent a massive fireball into the sky near Tehran remains unclear, as does the cause of the blast.

The blast shook homes, rattled windows and lit up the horizon early Friday in the Alborz Mountains.

Defense Ministry spokesman Davood Abdi blamed the blast on a leaking gas he did not identify and said no one was killed in the explosion.

The gas storage area sits near what analysts describe as Iran’s Khojir missile facility. The explosion appears to have struck a facility for the Shahid Bakeri Industrial Group, which makes solid-propellant rockets, said Fabian Hinz, a researcher at the James Martin Center for Nonproliferation Studies at the Middlebury Institute of International Studies in Monterey, Calif.

The Washington-based Center for Strategic and International Studies identified Khojir as the “site of numerous tunnels, some suspected of use for arms assembly.” Large industrial buildings at the site visible from satellite photographs also suggest missile assembly being conducted there.

The U.S. Defense Intelligence Agency says Iran overall has the largest underground facility program in the Middle East.