Six people were on board the plane, a Learjet 55 adapted for medical transport, according to a spokesperson for the company behind the transport. In addition to a mother and her daughter, who had received care in the USA for a life-threatening illness, there were four crew members. All were Mexican citizens.
The company cannot confirm that anyone on board survived the crash, which occurred on Friday evening, local time.
"Our thoughts are with the patient's relatives, our staff, their families, and others who may have been affected on the ground," the company writes in a statement.
Residential building caught fire
The plane crashed at a usually heavily trafficked intersection in a densely populated area, near the large shopping center Roosevelt Mall, with stores and restaurants. In video clips on social media, the plane can be seen crashing and then a large fireball.
Several residential buildings caught fire and cars were damaged, said Philadelphia's Mayor Cherelle Parker at a press conference a short time after the crash.
Six people who were on the ground were taken to hospital. Three of them have been able to go home again, and the condition of the others is stable, according to the university hospital in northeastern Philadelphia.
Trump: "Very sad"
The crash occurred just days after the severe plane crash in Washington, where 67 people died. US President Donald Trump writes in a post on his platform Truth Social that "more souls have been lost" and that he is "very sad" about what happened.
Michael Schiavone, 37, who lives near the crash site, was at home when he suddenly heard a loud bang that shook the house. He says it was like a small earthquake. When he went through the images on his surveillance camera, he saw something that looked like a robot crashing down a bit away.
It was a big explosion, so at first I thought we were under attack, he says.
Unclear circumstances
Pennsylvania Governor Josh Shapiro says that the state is making all its resources available for the rescue effort.
Flight data shows that the plane took off from Northeast Philadelphia Airport just after 6 pm on Friday local time but disappeared from the radar just half a minute later and crashed shortly after.
The plane, which was headed to Tijuana, was on its way to Missouri for a stopover. What caused the accident is not clear.
