A video posted on Xx shows the mass execution of about eight people in a square in a town south of Gaza, surrounded by a large crowd of onlookers.

Witnesses told the German news agency dpa by phone that Hamas accused those executed of collaborating with the Israeli army.

The BBC claims to have authentic video footage showing a public execution carried out last night by armed members of Hamas in Gaza. The videos show several men with guns lining up eight people with their hands tied behind their backs in a public square in front of a crowd.

Although the BBC has not been able to confirm the identities of the masked attackers, some of them are wearing green headbands linked to Hamas.

A moment later, the gunmen open fire, killing all eight. The crowd can be heard shouting" Allahu Akbar" - God is greatest in Arabic - as the attackers stand next to the body.

Markings visible in the video and comparing street layouts with public maps confirmed that the video was shot on Gaza's main road. Hamas in a statement, without providing any evidence, stated that the executed men were"criminals and Israeli collaborators".

Gaza has been rocked by internal violence in recent days, with reports of clashes between Hamas and rival clans within the strip. In the latest outbreak of violence over the weekend, dozens of people were killed when gunmen from Hamas clashed with members of the Dughmush family, a powerful clan in Gaza.

In a post on Facebook, a member of the Dugmus family called the executions a"criminal act". It is not known how Hamas chooses who to execute, because there is no fair trial, dpa points out.

The videos show some of the victims apparently being tortured before the execution, but the authenticity of the footage has not yet been confirmed. According to unconfirmed reports, emergency trials were held in which members of the Hamas security apparatus imposed death sentences.