A medevac plane crashed soon after takeoff in Philadelphia on Friday with a child and five others on board, the air ambulance company that operated it said, adding that it had not confirmed any survivors.

Jet Rescue Air Ambulance, based in Mexico and licensed to operate in the US, said its aircraft crashed with four crew members, one pediatric medical patient and the patient's mother on board.

"At this time we cannot confirm any survivors," the company said in a statement.

State and local officials said late on Friday they could not yet confirm how many people may have died on the ground after the plane slammed into a heavily populated portion of the city. Videos taken by witnesses of the crash clearly showed body parts strewn about the streets and inside nearby homes.

The Mexican government said all those on the plane were Mexican nationals, CNN reported.

The child was a girl on her way home with a final destination of Tijuana, Shai Gold, who works on corporate strategy with Jet Rescue Air Ambulance, told CNN. Her mother was also aboard, he said.

"We are terribly shocked by this tragic turn of events," Gold said. "This was a very seasoned crew. We are a leading air ambulance company, we fly 600 to 700 times a year."

He said the company had invested heavily in maintaining its aircraft to the highest international standards and that the plane that crashed had been in excellent flying condition.

"We really don't know what happened," Gold said.

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Pennsylvania Governor Josh Shapiro told a press conference at the crash scene that "we know there will be loss in this region."

"We want to offer our thoughts and our serious prayers for those that are grieving at this moment," Shapiro said.

President Donald Trump wrote on social media that it was "so sad to see the plane go down in Philadelphia, Pennsylvania. More innocent souls lost. Our people are totally engaged. First Responders are already being given credit for doing a great job."

The crash follows this week's collision of an American Airlines jet and a US Army Black Hawk helicopter over Washington DC, which killed 67 in the deadliest airplane crash in the US since 2009.

The Federal Aviation Administration said six people were on the Learjet 55 that crashed around 6:30 pm (0030 GMT) on Friday. Local media reported it was near the Roosevelt Mall in northeast Philadelphia and that there were multiple injuries on the ground.

Video aired on local TV stations showed the plane in a sharp dive before hitting the ground and exploding in a massive fireball.

Philadelphia Mayor Cherelle Parker told a press conference at the scene that several houses and cars had been engulfed in flames. She said the situation is "all hands on deck, that's where we are right now."

Officials said it was not clear what led to the crash. The weather was cold and rainy and with low visibility when the plane went down.

The air ambulance had left Northeast Philadelphia Airport and was headed to Springfield-Branson National Airport in Missouri, about 1,100 miles (1,800 km) to the southwest, the FAA said in a statement.

A large fire and several fire trucks were visible at the crash scene in images broadcast by the Philadelphia CBS affiliate. About two hours after the crash the fires were mostly out, according to TV images.

The Philadelphia police and fire departments did not respond to requests for comment.