Iranian security forces killed a teenage boy by firing a shotgun at him at point-blank range in the city of Mashhad, sources have told BBC Persian.

Abolfazl Adinezadeh, 17, skipped school to join anti-government protests on 8 October, but he never returned home.

Authorities have not commented. But his death certificate, obtained by the BBC, said he died as a result of liver and kidney damage caused by birdshot.

"What crime had he committed, that you sprayed his stomach with 24 birdshot?" Abolfazl's father pleaded at his funeral

Abolfazl's parents initially had no idea what had happened to him after he took part in the protests.

It was not until the next day that the education ministry telephoned and told them to pick him up from the local police station. But when they got there, they were told that he was dead.

The sources said the family was put under pressure to say that their son was a member of the Basij, a notorious paramilitary force that is involved in the violent crackdown on the protests.