The large, deadly explosion at an Iran military base in Iran on Nov. 12, which Iranian authorities have called an accident that set back research work there by a few days, appears to have been far more devastating than their description suggested, according to an analysis of newly released commercial satellite images of the blast site.

The images reveal vast destruction and chaotic disarray across a sprawling complex composed of more than a dozen buildings and large structures.

The Institute for Science and International Security, a private group in Washington, made the satellite images public Monday, along with an analysis of the damage. “It was pretty amazing to see that the entire facility was destroyed,” Paul Brannan, the report’s author, said Tuesday in an interview. “There were only a few buildings left standing.”