Australia's prime minister ordered a sweeping investigation Tuesday into allegations that teenagers were abused at a juvenile detention center, and suggested that there had been an institutional cover-up of the scandal.

Prime Minister Malcolm Turnbull said he would launch the Royal Commission — Australia's highest form of inquiry — after graphic footage emerged of teenage detainees being tear-gassed and stripped naked. In one instance, one of the teens was shackled to a restraint chair with a hood placed over his head, before being left alone for hours.

The footage, which aired on the Australian Broadcasting Corp.'s investigative program "Four Corners" on Monday, was filmed largely at a youth detention center in the Northern Territory city of Darwin between 2010 and 2015.

"We are determined to get to the bottom of this, we're determined to examine the extent to which there has been a culture of abuse and, indeed, whether there has been a culture of a cover-up," Turnbull told reporters. "Why was this abuse, this mistreatment, unrevealed for so long?"

When the tear gas incident occurred in 2014, officials said guards had used the chemical to subdue six teens who had staged a riot. But CCTV and video footage filmed by staff at the center appears to show that the tear gas was used after just one teen escaped his cell, while the other five remained locked in their cells. The guards are heard laughing as the teens cough and cry after multiple shots of tear gas were fired into the isolation wing where they were housed. One of the detainees can be heard saying he can't breathe.

In another video, a guard is seen picking up a 13-year-old and hurling him across the room onto his bed. The same boy is also seen in footage from a different Northern Territory detention facility being stripped naked and held face-down on his bed by three guards after he apparently threatened to hurt himself.

The Don Dale Youth Detention Centre has been the subject of complaints for years. Last year, a review of the facility by the Northern Territory Children's Commissioner found an excessive use of solitary confinement and inappropriate use of restraints at the center.

Human rights activists accused the government of ignoring the issue until it became public because the teens involved were indigenous. The Northern Territory has the highest rate of youth detention in the country, and 97 percent of detainees are Aboriginal.

"Amnesty International has repeatedly raised concerns of abuse of children being held in youth detention centers in the Northern Territory," Julian Cleary, Indigenous Rights Campaigner at Amnesty International Australia, said in a statement. "As this program shows, these are not isolated incidents. The (Northern Territory) Government has failed to deal with systemic issues with the treatment of children in its youth detention system."

Northern Territory Chief Minister Adam Giles said he had never seen the footage before it aired on Monday night, and blamed a "culture of cover-up" within the corrections system for the government's lack of action until now.

"I sat and watched the footage and recognized horror through my eyes," Giles told reporters in Darwin.

Giles said he had removed Northern Territory Corrections Minister John Elferink from his position on Tuesday.

The royal commission was expected to begin holding hearings as early as September, with a final report due to be released early next year, Giles said.