An 8-year-old girl died while in US Customs and Border Protection custody in Harlingen, Texas, the agency said Wednesday.

The girl and her family were in custody at a CBP facility when she "experienced a medical emergency," the agency said in a news release Wednesday night, without providing details.

"Emergency Medical Services were called to the station and transported her to the local hospital where she was pronounced dead," the release said.

The Office of Professional Responsibility is investigating her death, as is consistent with protocol, CBP officials said.

The child's death comes days after an unaccompanied Honduran 17-year-old housed at a Florida shelter died while under the care of the US Department of Health and Human Services' Office of Refugee Resettlement, according to a congressional notice obtained by CNN last week.

Last week, immigration officials said in a court filing that surging migration coupled with the termination of Title 42 "is overwhelming U.S. Customs and Border Protection (CBP) facilities, risking widespread health and safety risks to migrants, government employees, and the public."

Detention facilities along the US-Mexico border surpassed capacity after an uptick in migrant crossings ahead of the expiration of Title 42, a Covid-era border restriction that was lifted last week.