The government says the 16-year-old fell and hit her head after experiencing a drop in blood pressure.

Armita Geravand, 16, died in a hospital in the capital after 28 days of being in the intensive care unit, state media confirmed on Saturday.

The incident happened on October 1 when Geravand, who was not wearing the mandatory headscarf required by Iranian law, entered the Shohada metro station.

CCTV footage released by Iranian authorities showed Geravand entering the station, going into a small shop inside, and then getting into a metro car with two other school friends.

The footage, this time from outside the metro car where the incident took place, then shows one of the friends backing up a moment after entering the metro car, and it appears someone has fallen. Geravand is then seen being carried out of the car completely unconscious.

No footage was shown from inside the metro car as authorities said there were no cameras inside.

Foreign-based human rights organisations and activists have claimed Geravand was harassed by government agents for the absence of her hijab.

The government has denied this allegation, saying she experienced a drop in blood pressure which caused her to fall and hit her head.

State media also released an interview with Geravand’s parents who said she fell and there was no physical altercation. Activists say the video may have been filmed under duress, a practice the government previously denied engaging in.

A report by a foreign-based rights group earlier this month said Geravand’s mother was arrested. The claim was denied by the Iranian judiciary.

The incident came more than a year after the death in police custody of 22-year-old Mahsa Amini, who was arrested by the morality police in Tehran for allegedly not adhering to the mandatory hijab rules in place since Iran’s 1979 Islamic Revolution.

Amini’s death sparked widespread protests across Iran that lasted for months and turned deadly.

A United Nations fact-finding mission was established following the protests, with Iran saying it wouldn’t not cooperate as it sees it as politically motivated to exert pressure on Tehran.

Amnesty International earlier this month released a statement to call on the Iranian government to allow for an independent investigation into Geravand’s death, which would also include the UN mission.

A new hijab law, which will bring new and harsher penalties for people found by authorities to be non-compliant with mandatory hijab requirements, is currently undergoing final consideration.