The film clips, whose authenticity has been verified by the British public service company, show how armed men line up eight people with tied hands and then shoot them dead.
The execution was carried out in a square in front of a larger crowd, according to the film clips.
BBC has not been able to confirm that the men who carried out the execution belong to Hamas, but notes that some of them appear to be wearing the green headbands associated with the terrorist-stamped movement that controls Gaza.
Hamas states in a statement according to BBC that the eight were "criminals and collaborators with Israel".
Dozens of people were killed over the past weekend in clashes between Hamas and armed members of a powerful Palestinian clan in Gaza.
A member of the clan writes in a post on Facebook that the executions constitute a criminal act.
