(London Express) The gang, believed to be from Afghanistan, were filming the three youngsters aged 15, 16 and 17 on their mobile phones at the Sophienhof shopping centre in Kiel, northern Germany.
Anxious passers-by, who were concerned that the mob might attack someone, called police who scrambled to the scene.
But some police officers were left injured after they were attacked by some of the group who became violent.
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Four men were arrested but three later released without charge.