The jet was on a medical transport mission on Friday evening and carrying four crew members, a child patient and the patient's escort, Jet Rescue Air Ambulance, a medical aircraft company, said in a statement, AzVision.az reports, citing BBC.
"We know that there will be loss," Pennsylvania Gov Josh Shapiro said during a news conference at the scene of the crash, calling it an "awful aviation disaster".
Emergency crews rushed to the evening crash scene as residents crowded streets littered with fiery debris and pieces of the aircraft.
Witnesses described a chaotic scene with people who were injured and structures ablaze.
The child on board the plane was receiving care in the US for a life-threatening condition and was returning to Tijuana, Mexico, Shai Gold, a spokesman for Jet Rescue Air Ambulance, told a local NBC outlet.
The girl was accompanied by her mother, a pilot, a copilot, a doctor and a paramedic, the spokesman said.
Mr Gold told NBC the child's treatment was sponsored by a third-partner charity.
"She fought quite a lot to survive, and unfortunately, this tragedy on the way home," he said.
The Mexican Consulate in Philadelphia put out a notice on X for Mexican nationals affected by the incident to call a helpline.
Philadelphia Mayor Cherelle Parker said city officials do not know the number of fatalities, but the city is "asking for prayers for anyone and everyone that may have been affected".
"If you see debris, call 911, don't touch anything," she told city residents.
The crash happened just blocks from the Roosevelt Mall, a three-storey shopping center in a densely populated part of Philadelphia, the fifth biggest city in the US.
The area where the crash occurred is filled with terraced housing and shops.
AzVision.az
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