Nineteen people were killed and six injured on Tuesday in an explosion at a medical clinic in the north of the Iranian capital Tehran, the official IRIB news agency reported, quoting state officials.

Axar.az reports citing foreign media that a gas leak caused the blast, Tehran Deputy Governor Hamid Reza Goudarzi told state television.

A video posted on social media appeared to show multiple explosions at the north Tehran site and another showed firefighters using a ladder to reach the roof of the building.

The clinic, which had 25 employees inside at the time of the blast, primarily carries out light surgeries and medical imaging, Harirchi said.