Large flash lights up Tehran night sky
A bright and large flash of light was seen in the night sky over Tehran early on Friday in images shared widely on social media, Iran's Fars news agency reported.
"In the early hours after midnight on Friday, a number of social media users reported seeing an orange light in the eastern part of Tehran," said Fars, which is close to ultra-conservatives.
"In the videos sent by (our) readers, this light is seen for a few seconds," it reported, adding it was following up the issue with the relevant authorities.
Fars said later that the flash was caused by "an industrial gas tank explosion" near a facility belonging to the defence ministry.
It cited an "informed source" and said the site of the incident was not related to the military.
"At the entrance of the (nearby) Parchin military zone, there is no movement or traffic of fire and rescue vehicles," Fars added.
Mehr news agency had said a "terrible sound" was heard.
"The cause of this sound and light is not yet known, but it was clearly heard in Pardis, in Boumhen and surrounding areas" of the Iranian capital.
State television said various institutions were investigating the issue. Fars said police were involved in the investigation.