Pakistani authorities are investigating a video that appears to show paramilitary forces shooting dead an unarmed teenager.
A spokesman for the Rangers said its forces detained 18-year-old Afsar Shah because he was attempting to rob people in a park in Karachi on Wednesday. The spokesman said Mr Shah was shot because he was trying to grab a Ranger's rifle.
But video screened on local television shows a man in civilian clothes wrestling what appears to be a gun from Mr Shah and kicking him toward a group of Rangers. Mr Shah says it is only a toy gun and pleads with a Ranger who points his rifle at his neck.
The men surround Mr Shah and point their guns at him. He moves toward one Ranger with his arms outstretched, saying "No, no, don't kill me brother." He is pushed back and shot twice in the hand and leg.