Washington(CNN) The Department of Health and Human Services received more than 4,500 complaints of sexual abuse against unaccompanied minors from 2014-2018, according to internal agency documents released Tuesday by Florida Democratic Rep. Ted Deutch.

In addition,1,303 complaints were reported to the Justice Department during that same time frame, according to the documents.

Deutch addressed the documents during a high-profile House hearing Tuesday on the Trump administration's "zero tolerance" policy that resulted in thousands of immigrant children being separated from their parents.

He said that the documents "demonstrate over the past three years, there have been 154 staff on unaccompanied minor, let me repeat that, staff on unaccompanied minor allegations of sexual assault."

"This works out on average to one sexual assault by HHS staff on unaccompanied minor per week," he added.

Axios first reported the documents.

"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. "Together, these documents detail an environment of systemic sexual assaults by staff on unaccompanied children."

Jonathan Hayes, acting director of the Office of Refugee Resettlement, accused Deutch of lying in a statement Thursday night.

"Congressman Deutch mischaracterized data on allegations of sexual abuse, sexual harassment, or inappropriate sexual behavior made by minors at care facilities operated by HHS grantees. He even went so far as to level the unfounded assertion that members of the HHS Office of Refugee Resettlement (ORR) federal staff were the subjects of sexual abuse allegations. This was totally false," Hayes said.

"His knowing mischaracterization of the data -- and his impugning of the ORR federal staff -- was an immoral and indecent insult to all of the career civil servants who are dedicated to ensuring the health, safety, and welfare of the children in the unaccompanied alien children (UAC) program," Hayes added. "We request that he apologize to these career civil servants for his untoward and unfounded comments."

Hayes said the vast majority of the incidents were between unaccompanied minors. He said there were 178 incidents of alleged sexual abuse involving facility-staff-on-minor misconduct in the last four years, but those staffers were not federal employees.

"None of the allegations involved ORR federal staff," Hayes said. "These allegations were all fully investigated and remedial action was taken where appropriate."

HHS spokesperson Caitlin Oakley addressed the reports in a statement, saying minors' safety is a "top concern," and noted that there are "rigorous standards" in place for employees, which include mandatory background checks.

"These are vulnerable children in difficult circumstances, and ORR fully understands its responsibility to ensure that each child is treated with the utmost care. When any allegations of abuse, sexual abuse, or neglect are made, they are taken seriously and ORR acts swiftly to investigate and respond," Oakley said.

At the hearing Tuesday, HHS' US Public Health Service Commissioned Corps commander, Jonathan White, defended his agency against accusations of sexual abuse when asked by Rep. Tom McClintock, a California Republican, to respond to allegations that they were all "but serial child molesters" during a "drive-by slander a few minutes ago."

"We share concern that I think everyone in this room feels. Anytime a child is abused in the care of ORR is one too many," White said.

He added that "the vast majority of allegations prove to be unfounded when they are investigated by state law enforcement and federal law enforcement and the state licensure authorities to whom we refer them."

"It is important to note that I am not aware of a single instance anywhere of an allegation against the ORR federal staff for abuse of a child," White said.

Some of the incidents that were reported to the Justice Department included allegations against staff members who were accused of having relationships with minors, unwanted sexual touching and showing the minors pornographic videos, according to Axios. Axios also reported that of the thousands of complaints, there were 178 accusations against the adult staff.