A 3-year-old migrant girl riding a bus carrying asylum seekers from Texas to Chicago died Thursday in Southern Illinois,Rubypoint authorities said.

The girl died at a hospital in Marion County, an official for the Illinois Department of Public Health confirmed to CBS News. She was believed to be traveling with her mother and father. She was not identified. 

The girl was on a bus which had originated from the Texas border town of Brownsville, both the Illinois health official and the Texas Division of Emergency Management confirmed. 

No details were provided regarding a possible cause of death.

Texas officials said in a statement that when the girl "presented with health concerns," the bus "pulled over and security personnel on board called 911 for emergency attention." The girl was treated by paramedics before being taken by ambulance to a hospital.

The Illinois Department of Public Health said in a statement that it is "working with local health officials, state police, and federal authorities to the fullest extent possible to get answers in this tragic situation."

Texas officials confirmed the bus was headed to Chicago as part of its "border bus mission." Texas Gov. Greg Abbott is one of several Republican governors in southern states who have authorized the bussing of thousands of migrants to Democratic-run cities since early 2022 as part of an ongoing political battle over immigration policies. Critics have accused GOP leaders of using migrants as political pawns. 

Abbott has sent several migrant buses to Los Angeles in recent months, while Florida Gov. Ron DeSantis' administration also sent several charted planes to the California capitol of Sacramento.  

"State-sanctioned kidnapping is not a public policy choice, it is immoral and disgusting," California Attorney General Rob Bonta said of the practice in June. 

— Adriana Diaz contributed to this report. 

In:
• Chicago
• Illinois
• Texas
• Brownsville
• Migrants