Screenshot from a video in which members of Greece's extreme-right Golden Dawn party pose as police to check migrant market traders' papers - and then attack a stall.

Screenshot from a video in which members of Greece's extreme-right Golden Dawn party pose as police to check migrant market traders’ papers – and then attack a stall.

Twitter users are promoting an international petition to urge a full criminal investigation into the Golden Dawn party in Greece.

This video, uploaded to YouTube on September 9, 2012, by user  appears to show supporters from Greece's extreme-right Golden Dawn party in the town of Rafina, near Athens, asking to see migrant vendors’ residence papers. Shortly afterwards another group is seen kicking over one of the stalls and smashing up merchandise. Twitter users are promoting an international petition to urge a full criminal investigation into the Golden Dawn party in Greece. Sign the petition here.