Police in Illinois are defending the violent arrest of a 17-year-old after footage of officers punching him in the head sparked protests.
The footage showed Hadi Abuatelah, who had fled police after a traffic stop in the village of Oak Lawn, being repeatedly punched in the legs and head by three officers on Wednesday.
Police say he was reaching for his bag, where they later found a gun.
The clip went viral, prompting several hundred protesters to accuse police of brutalising the teenager and using excessive force.
Hadi remains hospitalised and suffered fractures to his face, skull, and pelvis and swelling of his brain, his mother Dena Natour and lawyers told a news conference.
Oak Lawn Police Chief Daniel Vittorio defended the officers' actions and said it was in line with their training, in a news conference on Thursday.
Mr Vittorio alleged that the teenager continued reaching for a shoulder bag that contained a loaded semi-automatic pistol as he struggled with officers.
He said the teenager did not stop reaching for the bag until a third officer shocked him with a "drive stun" from his Taser, which causes severe pain.
"What concerns me is a 16-year-old running around with a gun," Mr Vittorio continued, misstating his age.
The teenager's mother said she did not know that her son owned or carried a gun and that he had not had any previous run-ins with police.
Ms Natour said: "When I saw the video, my stomach was in knots.
"You feel so helpless, watching your child, seeing three oversized men just beating him."
The police chief said the department was conducting an internal investigation of the arrest and that it intended to seek charges against the teenager.
Mr Vittorio said that none of the three officers involved have been suspended or moved off active duty, though two of the officers have not returned to work after suffering injuries themselves during the arrest.
Protesters are calling for the department to fire the three officers.