(CNN) A former youth care worker is accused of sexually abusing eight teenage boys at a federally funded Arizona migrant shelter that's part of the US government's network of privately run facilities intended to care for unaccompanied minors, according to court documents.

Levian Pacheco has been charged with eight counts of abusive sexual contact of a ward and three counts of sexual abuse of a ward in connection with incidents from August 2016 to July 2017 at Southwest Key's Casa Kokopelli facility in Mesa, court records show. The case was first reported by ProPublica.

The eight unaccompanied minors were between 15 and 17, the documents said.

"The age of these individuals, their separation from parents and relatives, and the hazardous journey they take make unaccompanied alien children especially vulnerable to human trafficking, exploitation and abuse," an affidavit said.

Pacheco, who was indicted in August 2017, denies the allegations, according to court documents. There was no immediate comment from Pacheco's federal public defender.

"The allegations include that the defendant touched six of the victims on their genitalia over their clothing, and that he performed oral sex on two of the victims," according to a proposed stipulated joint description of the case. Pacheco is also accused of attempting to have anal sex with one of the boys.

Jeff Eller, a Southwest Key spokesman, said in a statement that employees accused of abuse are immediately suspended and police contacted. The nonprofit group runs migrant children's shelters in several states, including Arizona, Texas and California.

"This is what we did in this case," he said. "We report these cases to law enforcement and state agencies when they happen."

Eller said the alleged abuse was reported to state authorities as well as the Office of Refugee Resettlement within the US Department of Health and Human Services, which is responsible for the care and custody of unaccompanied migrant children.

"We educate every child in our care upon arrival to the facility of their right to be free from abuse or neglect in this program and this country," he said. "This message is repeated to the children throughout the duration of their stay at our shelters."

The US Department of Health and Human Services said in a statement that it issued a stop placement and removed all children from the Mesa, Arizona, shelter.

"These are vulnerable children in difficult circumstances, and the Office of Refugee Resettlement at HHS' Administration for Children and Families treats our responsibility for each child with the utmost care," the statement said. "Any allegation of abuse or neglect is taken seriously, investigated by the Office of Refugee Resettlement, and appropriate action is taken."

Pacheco worked for Southwest Key from May 2016 through July 2017. His trial is set for later this month.

The case is the latest in a series of abuse allegations involving the vast government network of shelters for young migrants.

The girl and two of her roommates accused Fernando Magaz Negrete, 32, of kissing her at the Phoenix facility in June, according to a probable cause affidavit obtained by CNN affiliate KTVK

One of the roommates also alleged Negrete inappropriately touched the girl, the affidavit said. Negrete, during an interview with detectives, admitted kissing the teen, according to the affidavit.

The Maricopa County public defender's office said a public defender will represent Negrete but said that one hadn't been assigned yet.

The Phoenix facility is known to house children separated from their parents at the border. Southwest Key's Eller told CNN on Thursday he couldn't say if the alleged victim was a minor separated from her parents due to Office of Refugee Resettlement restrictions.

The investigative nonprofit said police reports and call logs also document allegations of fights and missing children.