An Iranian teenage girl injured weeks ago in a mysterious incident on Tehran’s Metro while not wearing a head scarf has died, state media has reported.

The death of Armita Geravand, 16, comes after her being in a coma for weeks and after the one-year anniversary of the death of Mahsa Amini and the nationwide protests it sparked.

Iran’s state-run IRNA news agency reported her death.

What happened in the few seconds after Armita Geravand entered the train on October 1 remains in question.

While a friend told Iranian state television that she hit her head on the station’s platform, the soundless footage aired by the broadcaster from outside of the car is blocked by a bystander. Just seconds later, her limp body is carried off.

Ms Geravand’s mother and father appeared in state media footage saying a blood pressure issue, a fall or perhaps both contributed to their daughter’s injury.

Activists abroad have alleged she may have been pushed or attacked because she was not wearing the hijab.

They also demanded an independent investigation by the United Nations’ fact-finding mission on Iran, citing the theocracy’s use of pressure on victims’ families and state TV’s history of airing hundreds of coerced confessions.

The IRNA report did not touch on any of the controversy surrounding Ms Geravand’s injury.

“Unfortunately, the brain damage to the victim caused her to spend some time in a coma and she died a few minutes ago,” the IRNA report read.

“According to the official theory of Armita Geravand doctors, after a sudden drop in blood pressure, she suffered a fall, a brain injury, followed by continuous convulsions, decreased cerebral oxygenation and a cerebral edema.”

Ms Geravand’s injury also came as Iran has put its morality police — whom activists implicate in Ms Amini’s death — back on the street, and as lawmakers push to enforce even stricter penalties for those flouting the required head covering.

Ms Amini died in a hospital on September 16 last year after she was detained by Iranian morality police on allegations of improperly wearing the hijab.

Suspicions that she was beaten during her arrest led to mass protests that represented the largest challenge to Iran’s theocratic government since the revolution.

Since those large-scale protests subsided, many women in Tehran could be seen without the hijab in defiance of the law.

On Saturday, US deputy special envoy for Iran Abram Paley wrote online that he was mourning Ms Geravand’s death.

“Iran’s state-sponsored violence against women & girls has been devastating for so many families in Iran & abroad,” he wrote.