A loud explosion at a military plant in Iran's central city of Isfahan was caused by a drone attack, Iranian state media reported on Sunday, citing the defense ministry.
"One of (the drones) was hit by the air defense and the other two were caught in defense traps and blew up. Fortunately, this unsuccessful attack did not cause any loss of life and caused minor damage to the workshop's roof," the ministry said in a statement carried out by the state news agency IRNA.
"The explosion took place in one of the munitions manufacturing centers of the defense ministry and, according to an announcement by the deputy Esfahan governor for security, there were no casualties," IRIB news agency reported.
The official, Mohammad Reza Jannesar, later told state television: "The damages are being investigated as well as the causes and elements that caused this explosion and will be announced later."
There have been a number of explosions and fires around Iranian military, nuclear and industrial facilities in the past few years.
The blasts at Iranian sites have at times caused concern amid tensions over Iran's nuclear program with Israel and the United States.
Israel has long threatened military action against Iran if indirect talks between Washington and Tehran fail to salvage a 2015 nuclear pact.