Police are quizzing three teenagers over a Facebook video that has been viewed more than 100,000 times online.
Just after 3.30pm, police announced they had arrested three 13-year-old boys on suspicion of assault following the video - which appears to show a young boy being chased, kicked and punched by youths - being shared on social media.
The boys, who are from the Heaton area of Bradford, remain in custody.
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Police have also spoken to the family of the 12-year-old victim, who have confirmed that he is safe and well.
Enquiries into the matter are continuing.
Detective Chief Inspector Terry Long, of Bradford District Police, said: "I would like to thank the public for bringing this incident to our attention, and would like to reassure them that any similar reports will be dealt with positively."
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