An Afghan infant traveling with her father on a C-17 military plane died after landing at the Philadelphia International Airport, CBS News reports. A Department of Defense spokesperson confirmed Thursday that the child became “unresponsive” on the flight from Germany’s Ramstein Air Base to the United States. After landing early on Wednesday morning, the baby and her father were brought to the Children’s Hospital of Philadelphia, where she was pronounced dead shortly afterward. Both the Philadelphia Police Department and the Medical Examiner’s Office are investigating the incident.

According to the city’s released data, Philadelphia processed more than 3,500 Afghan evacuees between Aug. 28 and Sept. 1. So far, roughly 24,000 refugees have been admitted to the U.S. after being flown out of Kabul. As of Thursday, CBS reported, more than 36,000 Afghans are still waiting to be processed at military bases in the Middle East and Europe.