All 143 passengers and crew have escaped after a Boeing 737 plane skidded off a runway and landed in a river during a “terrifying” attempted landing at an airport in Jacksonville, Florida. [See footnote]

The military-chartered Miami Air international plane was trying to land in a thunderstorm at the naval air station in Jacksonville en route from Guántanamo Bay in Cuba at around 9.40pm local time when it slid off the runway into the St Johns river, a statement from the navy airport said.

Officials said the 136 passengers and seven crew were alive and accounted for after the plane ditched in shallow water.

Twenty-one adults were transported to local hospitals for minor injuries but were in good condition.

Officials did not immediately say what caused the plane to leave the runway. On Saturday the National Transportation Safety Board said 16 investigators were arriving to determine the cause.

Emergency crews work next to a Boeing 737 aircraft arriving from Guántanamo Bay, Cuba, on 3 May. Photograph: Thomas A Higgins/AP

A Boeing spokesman said Friday that the company was aware of the incident and was gathering information.

The mayor of Jacksonville said on Twitter that everyone on board the flight was “alive and accounted for” but that crews were working to control jet fuel on the water.

“The plane was not submerged. Every person is alive and accounted for,” the Jacksonville sheriff’s office said on Twitter.

Plane slides off runway into river in Jacksonville, Florida https://t.co/YPpdEyZ6zp pic.twitter.com/ACeadSy14O — CBS News (@CBSNews) May 4, 2019

A passenger on board the plane, lawyer Cheryl Bormann, told CNN in an interview that the flight, which had been four hours late in departing, made a “really hard landing” in Jacksonville amid thunder and lightning.

“We came down, the plane literally hit the ground and bounced, it was clear the pilot did not have total control of the plane, it bounced again,” she said, adding that the experience was “terrifying”.

Bormann said she hit her head on a plastic tray on the seat in front of her as the plane veered sideways and off the runway. “We were in the water, we couldn’t tell where we were, whether it was a river or an ocean.”

Bormann described emerging from the plane onto the wing as oxygen masks deployed and smelling the jet fuel that she said was leaking into the water.

Bormann, from Chicago, said that most of the passengers were connected to the military and helped each other out of their seats and onto a wing, where they were assisted after some time into a raft.

The Jacksonville fire and rescue department posted on Twitter that about 90 personnel responded to the scene, adding that the department’s special operations team had trained with marine units for a similar incident earlier Friday.

Later, Capt Michael Connor, the commanding officer of NAS Jacksonville, said during a news conference that passengers were a mix of civilian and military personnel. Some were staying in the area, while others were set to fly on to other parts of the country.

Connor acknowledged that it could have been much worse. “I think it is a miracle,” Connor said. “We could be talking about a different story.”

It wasn’t known how long it would take to remove the plane from the river, but Connor said the landing gear appeared to be resting on the river bed, making it unlikely for the aircraft to float away. He said crews began working to contain any jet fuel leaks almost immediately after securing the passengers’ safety.

#JSO Marine Unit was called to assist @NASJax_ in reference to a commercial airplane in shallow water. The plane was not submerged. Every person is alive and accounted for. pic.twitter.com/4n1Fyu5nTS — Jax Sheriff's Office (@JSOPIO) May 4, 2019

Miami Air international is a charter airline operating a fleet of Boeing 737-800 aircraft. Representatives for the airline could not immediately be reached for comment by Reuters on Friday evening.

The charter company is contracted by the military for its twice-weekly “rotator” roundtrip service between the US and Guántanamo, said Bill Dougherty, a spokesman for the Jacksonville base.

It flies every Tuesday and Friday from the naval station Norfolk in Virginia to the Jacksonville air station and on to Cuba. It then flies back to Virginia with a stop again at Jacksonville, he said.

The rotator service typically flies military personnel, family members, contractors and other civilians traveling from the United States to Guántanamo Bay. But officials said the mix of civilians and military personnel on the plane that crash-landed was not immediately known.

Reuters and Associated Press also contributed to this report.

• This footnote was added on 6 May 2019 for the avoidance of doubt: the Boeing 737-800 is a different aircraft from the 737 Max 8 widely grounded after two fatal crashes.