A Boeing 737 with 143 passengers on the St. Johns River in Jacksonville: NPR

A Boeing 737 arriving at the Naval Air Station in Jacksonville, Florida, from Guantanamo Bay, Cuba, skidded into the St. Johns River on Friday night.

The 136 passengers and seven flight crew members are on board and are still dead, officials at the Naval Air Station in Jacksonville said in a statement. Twenty-one adults were transported to local hospitals with minor injuries reported.

"The non-critical status is what we had from the 21 people transported [to local hospitals]Jacksonville Fire and Rescue Department spokesman Tom Francis said.

The plane that left the track at 21:40. And, was in "shallow water" and "not submerged", the Jacksonville Sheriff's Office m said on Twitter.

Navy security and emergency response personnel are on scene and an investigation into the accident is underway, the Navy said.

Boeing also said that he was investigating the incident.

"We are aware of an incident in Jacksonville, Florida, and we are gathering information," Boeing said. in a tweet.

Mayor of Jacksonville, Lenny Curry published updates on Twitter. He added that the White House has been calling for help as the situation evolves.

The officials did not immediately explain why the plane had left the runway.

This is a story in development. Details may change as more information becomes available.