Powerful explosion rocks health clinic in Iranian capital
The blast at Sina At'har health centre caused damage to buildings in the vicinity and sent a plume of thick black smoke into the night sky, state television reported.
Videos of the incident quickly surfaced across social media platforms, with initial reports blaming the blast on a gas leak at the health facility.
"An explosion was reported at 20:56 (1626 GMT) followed by a fire at Sina At'har clinic. Medical units were dispatched immediately," the EMS said in a statement.
"The death of 13 people has been confirmed. Six have also been injured and transferred" to a hospital, the service added, referring to an earlier death toll.
Ten of the casualties were women, Tehran's police chief Hossein Rahimi told ISNA.
Tehran fire department spokesman Jalal Maleki told state TV that the explosion occurred as gas canisters caught fire in the clinic's basement.
Some of the victims "were in upper floors in operation rooms, who were either patients being operated on or those with them," he said.
"They unfortunately lost their lives due to the heat and thick smoke."
The blaze was extinguished around two hours later.
Tuesday's explosion came just days after another blast lit up the night sky in images widely shared on social media, amid speculation that the explosion could have been from a military strike.
Iran's defence ministry on Friday confirmed the blast was caused by an industrial gas tank that blew up just before midnight.
"A gas tank exploded in the Parchin public area. Thank God, there were no casualties," defence ministry spokesman Brigadier General Davoud Abdi said.
Fars news agency, which is close to ultra-conservatives in Iran, said that according to "videos sent by [our] readers, this light was seen for a few seconds".
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," the news agency added.
Fars news agency said that the flash of light was caused by "an industrial gas tank explosion" near a facility belonging to the defence ministry.
Mehr news agency 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, it said.