Legislators grilled Mayor Bill de Blasio's jails commissioner for more than two hours Wednesday about whether the administration is moving fast enough to fix a system the U.S. Justice Department says brutalizes teenage inmates.

Correction Commissioner Joseph Ponte, testifying at a City Council oversight hearing, conceded that his agency "needs to radically change." He said he doesn't disagree with the Justice Department's scathing 79-page report from August finding "a deep-seated culture of violence" on Rikers Island.

But he faced criticism from lawmakers on a range of issues, including the speed of installing surveillance cameras and where to house the 250 or so 16- and 17-year-old inmates. The Justice Department has recommended moving them off Rikers, as did several of the council members.

Ponte came under fire for his decision to promote men whom the department's own investigators said had "abdicated all responsibility" in a years-old numbers-fudging scandal on their watch involving jailhouse violence.

"I think they're competent individuals," Ponte said of William Clemons, who now holds the department's top uniformed position, and Turhan Gumusdere, now warden of Rikers' largest jail.

The allegations against the men -- which prompted de Blasio's own Department of Investigation to counsel against the promotions -- were not reflective of a person's "experience that goes well beyond a one-time event."

Council Speaker Melissa Mark-Viverito said she was baffled by the promotions. A draft report rejected by a Bloomberg-era jails commissioner had suggested they be demoted.

Since taking over in April, Ponte said, the staff-inmate ratio in the island's teen jail has been lowered to 15-to-1 from 33-to-1, all use-of-force incidents are to be investigated by a new in-house team, and solitary confinement is expected to end for the teens.

Ponte said he was meeting regularly with the Manhattan U.S. attorney's office, which issued the report, to come to a settlement about jail practices.

He said the agency has made strides and cut the number of so-called use-of-force incidents by guards at the teen jail from 28 in April to 18 in August.

The hearing was one of the most contentious since Mark-Viverito assumed the speakership in January. During one particularly heated exchange, Elias Husamudeen, first vice president of the Correction Officers' Benevolent Association, challenged committee members to name a way besides solitary confinement to discipline the worst-behaved juveniles.

When Councilwoman Elizabeth Crowley lamented that the "level of violence is out of control," Husamudeen interjected: "Liz, there's nothing that you can tell me about jail, just like there's nothing that I'm going to sit here and tell you about the City Council."