By Priscilla Alvarez, CNN

(CNN) -- During a House hearing Tuesday, Trump administration officials drew clear distinctions about each agency's role in the controversial "zero tolerance" immigration policy that resulted in separating thousands of children from their families -- seemingly punting responsibility on the different facets of the policy which continues to have repercussions nearly a year later.

House Judiciary Committee Chairman Jerry Nadler kicked off the hearing by slamming the administration.

"When a stranger rips a child from a parent's arms without any plan to reunify them, it is called kidnapping," he said.

Nadler's speech set the tone for the hearing, which is expected to be filled with testy exchanges between lawmakers and administration officials.

House Democrats have long denounced "zero tolerance," which called for the criminal prosecution of adults who illegally crossed the border and as a result, separated families.

Administration officials explained present day challenges, like an influx in family apprehensions, how the "zero tolerance" policy was rolled out, and defended efforts reunify families.

That provided little reprieve to Nadler, who immediately questioned Border Patrol Chief Carla Provost about the consequences of separations. Provost said there were "lessons learned," but also said that it's not Border Patrol's responsibility to reunify families, pointing to the Department of Health and Human Services instead.

Health and Human Services, however, did not develop the policy -- it was directed by the Justice Department. To that end, Democratic Rep. Hank Johnson asked James McHenry, the director of the Executive Office for Immigration Review, an agency within DOJ, about whether the agency provided any legal analysis on the policy. Johnson said he couldn't "discuss deliberations."

Lawmakers repeatedly raised concerns about the tracking of families who had been separated at the US-Mexico border. Lloyd, an HHS senior adviser who formerly served as the director of the Office of Refugee and Resettlement, disputed Democratic Rep. Sheila Jackson Lee's claim that children were not being properly tracked.

"I wouldn't agree with your characterization that there was not tracking. The tracking that occurred, occurred within our normal case management system," Lloyd said. "Our tracking of the circumstances under which kids come into our care is ongoing -- it never stopped it never began."

Lawmakers also pulled from newly-obtained documents.

Democratic Rep. Ted Deutch introduced a new set of HHS documents obtained by his office that showed thousands of allegations of sexual abuse against children in custody, prompting a heated back and forth between him and White.

"I am deeply concerned with documents that have been turned over by HHS that record a high number of sexual assaults on unaccompanied children in the custody of the Office of Refugee and Resettlement," Deutch said.

White interjected to say that it was not HHS staff, later adding, "this is a longer conversation."

House Democrats approve subpoenas

Nadler also blasted the administration for not turning over sufficient records in a timely manner.

"Even now months after the height of the crisis created by the implementation of its cruel and inhumane immigrant policies, basic questions remain unanswered," he said. "In part that is because the Department of Justice and the Department of Homeland Security, until last night, stonewalled the legitimate requests by this committee that were made over six weeks ago."

He added: "That is absolutely inexcusable."

A separate committee, the House Oversight Committee, voted Tuesday to issue subpoenas related to family separation.

The vote was bipartisan with Republicans Justin Amash of Michigan and Chip Roy of Texas voting with the Democrats. The subpoenas will be the first issued in the committee in the 116th Congress.

This story is breaking and will be updated.