Nineteen football fans who died in pre-match violence at a Cairo stadium earlier this week were killed by suffocation or in a stampede, the Egyptian Forensic Medicine Authority announced on Thursday.

Spokesman Hisham Abdel-Hameed told journalists that the authority had finished the autopsies of the 20 victims who died at the Air Defence Stadium on Sunday, and that reports had been pass on to the general prosecution, which is investigating the incident.

He stressed that the deaths had not been caused by gunshots or by teargas.

The health ministry and the police have said that all the victims of the violence, which injured at least 20 others, were crushed in a stampede.

Eyewitnesses however said the crowd stampeded after security forces fired teargas to disperse the fans, mostly from the Ultras fan group, who were trying to force their way into the stadium.