An explosion killed several members of the elite Revolutionary Guards at a military base in western Iran, reported local news agencies.
The Fars News Agency, which is close to the Guards, said that blast also injured several others, who were taken to hospitals in Khoramabad, some 300 miles (500 kilometers) southwest of capital.
The Guards' official website added that a fire ignited the base's ammunition depot, but did not indicate how the blaze had started.
Most Iranian news agencies described the explosion as accidental.
The Mashreghnews.ir news website was the sole outlet to give an exact toll, reporting that 12 guards and been killed and 20 injured. The site has ties to Iran's presidency.
Iran is battling separatist movements in the southeast along the border with Pakistan and in the northwest along the border with Iraq, but both these areas are hundreds of miles from Khoramabad.
On Sept. 12, a blast at a military parade in Mahabad, near Iraq, killed 12 people and prompted a cross-border retaliatory raid by Iranian forces. They blamed the attack on Kurdish separatists and followers of former Iraqi dictator Saddam Hussein.