The Learjet 55 departed from Northeast Philadelphia Airport en route to Springfield-Branson National Airport in Missouri, the Federal Aviation Administration said in a statement.

On board were the pilot, a copilot, a physician, a paramedic, the patient, and the escort for the patient, Jet Rescue Air Ambulance said.

Late Friday night, Mexico's Ministry of Foreign Affairs said on X that all six on board the Learjet were Mexican nationals. It said its consulates were ready to provide support to relatives of those on the plane.

The Consulate of Mexico said officials have contacted the families of all six people.

"The necessary consular assistance is being provided and working with the authorities to clarify what has happened," the Consulate said in a translated post on Facebook.

A spokesperson for the company, Shai Gold, told NBC Philadelphia the patient was a child who had come to the U.S. for "life-saving treatment" and was returning to Mexico.

"The treatment ran its course. She was ready to go home, and we were contracted to bring her back home to Mexico," Gold said. "Ultimate destination was the Tijuana International Airport and was scheduled to go home by ground ambulance." 

He said the cost of the flight was covered by an international charity.

A spokesperson for Shriners Children's Philadelphia hospital said in a statement that the child had been treated at the institution and was traveling with her mother.

"Shriners Children’s is heartbroken to confirm that one of our pediatric patients and the child’s mother were aboard the Jet Rescue Air Ambulance that crashed in Philadelphia this evening," the spokesperson said.

The identities of the people on board have not been publicly released.

The plane crashed around 6:30 p.m. near Roosevelt Mall, an outdoor shopping center about 3 miles from the airport, according to officials.

Odalis Acosta, 29, was helping a customer at Four Seasons Diner when “everything shook.”

“You heard the explosion. I look to the side and I see through the window the big ball of explosion,” she told NBC News.

People in the restaurant dropped to the ground as the glass around them shattered, she said. One customer was hit in the head by a heavy piece of metal.

Video showed smoke and fire in the area of the crash.

“The FAA and NTSB will investigate,” the FAA said, referring to the National Transportation Safety Board. “The NTSB will lead the investigation and will provide all updates.”

Pennsylvania Gov. Josh Shapiro said on X that he's in touch with Philadelphia officials and will provide updates as he gets them.

"We are offering all Commonwealth resources as they respond to the small private plane crash in Northeast Philly," he said.

Home camera video of the crash showed an airborne object descending at an angle in the distance. A fireball is then seen behind some rooflines.

Rev. Todd Sheridan Yeary, a former FAA air traffic controller, said that, having received clearance to take off and the aircraft's good reputation, something likely happened in the moments after its wheels left the ground.

"Something happened rather catastrophically after the aircraft lifted off," he said on NBC News NOW. "We don’t know exactly what it is."

He said the model of the jet is "high performance."

"It is very reliable," Yeary said. "It is very unusual to see what we’ve just witnessed."

Air temperature around the time of the crash was 49 degrees, with light rain, some fog, and a wind guest of 30 mph recorded just before 6 p.m., according to National Weather Service data for Philadelphia.

The crash comes just days after the deadliest aviation incident in the U.S. in years.

On Wednesday, 67 people were killed when a passenger plane collided midair with a Black Hawk military helicopter over the Potomac River near Washington, D.C.