According to the semi-official Iranian Students News Agency (Isna) said the fire was in an “explosive materials production unit”.

 Isna, quoting Iran’s defense industries organization, said: “Unfortunately, due to the incident, two workers of this production unit lost their lives.”

Some reports indicate a huge blast near the Parchin military site on Sunday evening at around 22:30 local time. 

According to a number of Tehran residents the blast was so huge that it was heard several Kilometers away and windows of buildings kilometers away were shattered. According to these residents, the glare from the blast could also be seen from a great distance.  

According to a number of residents tight security was imposed in the area near Parchin. 

Parchin is a vast military testing complex 30 kilometers southeast of Tehran, covering 42 square kilometers. 

The International Atomic Energy has been insisting on visiting a specific area of Parchin on the northern end of the complex since 2012.  It was after the IAEA received evidence in 2011 that at least one building on that area of Parchin was the location of high explosive tests related to the development of nuclear weapons.  According to the UN watchdog, a “foreign expert”  who had assisted Iran in working on developing a “high explosives” trigger could have contributed to the tests that took place in Parchin. 

The Iranian regime has denied access to the IAEA. According to the latest IAEA report in September 2014, the location has gone through substantial reconstruction and modifications since 2012, exacerbating the agency’s concerns. 

The Iranian regime provided a limited access of Parchin to the IAEA in 2005 but no access has been provided since then.