An engineer died and another employee was injured after an unexplained accident on Wednesday in a research center at the Parchin military site affiliated with Iran's Defense Ministry, the semi-official Fars news agency reported on Thursday.
Fars news said investigations into the cause of the accident were under way.
The Defense Ministry identified the engineer who died as Ehsun Ghadbeigi.
Situated 60km southeast of Tehran, Parchin is a sensitive military site housing several industrial and research units, where Western security services believe Iran carried out tests related to nuclear bomb detonations more than a decade ago.
In 2015, Tehran allowed the UN nuclear watchdog to take environmental samples at the military site to make an assessment of "possible military dimensions" of Iran's nuclear program.
Iran’s missile and space programs have suffered a series of mysterious explosions in recent years. A giant unexplained blast struck in the area of Parchin in June 2020, rattling the capital and sending a massive fireball into the sky near Tehran.