Tarek Abu Khdeir, 15, was beaten in the Shufat neighborhood at around 8 p.m. by Israeli police in the yard of his uncle’s home and arrested without charges, Addameer said on its website Friday.
The boy was taken to a police station following the beating, and police delayed treatment of his wounds until 1:20 a.m., when he was taken to Hadassa Hospital.
His family was not permitted to see Tarek until he was hospitalized, the rights group said.
His detention has been extended until Sunday morning, when a hearing will be held at the Court of First Instances in Jerusalem.
The teen is a student at Universal Academy of Florida high school in Tampa, local news website 10 News reported.
The Council on American-Islamic Relations called on the US State Department to secure Tarek’s release, the report said.
Tarek is one of 11 Palestinians who were beaten and arrested in the neighborhood on Thursday, Addameer said.
Widely-circulated video footage
Video footage of Tarek’s beating emerged Thursday
The video, posted on Youtube by Palestine Today TV shows what appears to be masked Israeli police in riot gear beating, kicking, and stamping on a Palestinian.
Israeli police spokesman Micky Rosenfeld did not answer Ma’an’s calls on Saturday, but he told the New York Times the video was “edited and biased.”
Tarek was born in the US and is a cousin of Muhammad Abu Khdeir, the 16-year-old Palestinian who was abducted and murdered Wednesday, in an apparent revenge attack against the killing of three Israeli teens who were buried the day before.
Abu Khdeir’s death sparked mass protests in East Jerusalem, especially the Shufat neighborhood, and other West Bank areas, leading to clashes with Israeli forces in which hundreds have been injured.
“State-sanctioned violence against children is unlawful and unacceptable,” Addameer said in its Friday report.
“Addameer urges immediate action and calls on the United Nations, the International Committee of the Red Cross, the United States consulate and all regional embassies and consulates, human rights organizations and journalists to attend Tarek Abu Khdeir’s hearing on Sunday 6 July to investigate the intensified aggression against Palestinian children.”