BROOKLYN - A video of dozens of teens violently attacking another teen in Brooklyn was uploaded to social media Monday.

Local activists are calling on parents and teens to stop the violence.

No witnesses stepped in to stop the attack, which happened near the Barclays Center in Downtown Brooklyn, but some uploaded it to Facebook, according to activists.

Also in the area, another teen was stabbed and two others were assaulted Monday.

Activists say parents should keep their kids busy after school and instruct their children to do the right thing in violent situations, rather than joining into the fray.

Two teens were arrested in connection with the stabbing. That victim is recovering in the hospital, according to police.

Police are still trying to contact the victim of the assault posted on Facebook.