TEHERAN (NYTIMES) - A huge explosion in the area of a major Iranian military and weapons development base east of Teheran turned the skyline bright orange for several seconds early Friday (June 26), official news agencies reported.
A spokesman for the Defence Ministry, Brigadier General Davoud Abdi, told state television that a gas explosion had occurred in the general area of the Parchin military complex, a military and weapons development base, but said that there were no casualties and that the fire was under control.
"Our colleagues are present on the ground and investigating the incident carefully," Brig Gen Abdi said.
Many residents of Teheran and surrounding suburbs posted accounts on social media asking if others had seen the sky suddenly turning orange or had heard two consecutive booms.
"We suddenly saw this scene and we were all terrified," tweeted Hamid Reza, who posted a video he shot from a mountaintop in northern Teheran.
Teheran's head of emergency response told local news outlets that workers had received no immediate requests for ambulances or medical aid but were on standby.
Some military analysts questioned whether the explosion could have been an accident or sabotage, given the importance of the Parchin complex.
"Parchin is basically the largest military explosive manufacturing site in Iran," said Mr Fabian Hinz, a researcher at the James Martin Centre for Nonproliferation Studies at the Middlebury Institute of International Studies in Monterey, California. "They produce artillery rockets there and had tests related to nuclear weapons designs before 2003."
Mr Afghon Ostovar, an Iran scholar at the Naval Postgraduate School, said that given Iran's sensitivity about the base, "it's easy to smell a possible cover-up."
He added: "It could have also been an accident at a military site, possibly involving fuel for ballistic missiles. A third possibility, of course, is that it wasn't an accident but rather a form of sabotage."
Many Iranians on social media also cast doubt on the government's account of Friday's explosion.
Trust between the Iranian public and the government has eroded in the past few months as a series of crises, from protests to the shooting down of a Ukrainian Airlines jet and the coronavirus pandemic, have taken a toll after the public demanded answers and the government failed to be transparent.
"Chernobyl series part one," tweeted Morteza Seydabadi. "Gas explosion near a military base? Do you think we are stupid?"
Parchin has been the focus of heavy international scrutiny, and Iranian officials have long tried to keep its activities opaque.
For years, Iran refused to grant access to inspectors from the International Atomic Agency to visit Parchin, saying that as a military base it was off limits. In 2014, a huge explosion caused damage at Parchin and raised questions of sabotage, but international investigators were denied access.
By the time the head of the International Atomic Energy Agency was allowed to visit the site in 2015, it was empty, though the agency's report indicated that equipment had been removed.
A secret archive of the country's nuclear activity - which Israel said its intelligence agents stole three years later - included photos that appeared to show a giant metal chamber built to conduct high-explosive experiments in a building at Parchin.