Israeli security forces are using excessive force against protesters in East Jerusalem, Palestinian sources claimed as violence escalated in the wake of a Palestinian teenager's death.

A video that emerged on Thursday shows three Border Police officers hitting a Palestinian detainee who is cuffed and is lying on the floor. One of the officers appears to be sitting on the youth while his colleague is kicking and punching him. Another video of the incident, filmed from a different angle, shows the officers dragging the unconscious detainee away.

Over the past three days the police have been exercising a so-called policy of "containment" – keeping a distance from the rioters, avoiding arrests and keeping the violence from spreading. But as riots escalated on Thursday, six arrests were made in the East Jerusalem neighborhood of Shoafat. According to a Palestinian source, police brutality was involved in all six cases.

One of the individuals arresetd, Ahmad Jabarin, 14, complained of violence used against him while he was arrested and interrogated.

"They hit him and told him to curse his parents and Prophet Muhammad," said his brother, Kamel." Photos of other youths who were allegedly beaten up by cops have surfaced on social media.

According to a police spokesman, the incident featured in the video occurred while six "masked rioters" were being arrested. Three of them carried knives.

"They resisted arrest and attacked the soldiers," the spokesman said, adding that Molotov cocktails were hurled toward the force, an attack he deemed "nearly fatal."

Nevertheless, he said that the incident is being investigated.

According to the spokesman, some 15 soldiers and police officers were wounded in the riots in East Jerusalem on Thursday.

Riots continued on Friday ahead of the funeral of Muhammed Abu-Khdeir, the 16-year-old Palestinian whose body was found early Tuesday in a West Jerusalem forest.