Dec. 23 (UPI) -- Five people died when a Mexican navy plane crashed off the coast of Galveston, Texas, the Mexican military announced.

Mexican officials reported that a King Air ANX 1209 plane crashed into Galveston Bay carrying four navy members and four civilians.

The Mexican navy described the crashed aircraft as part of a humanitarian medical transport mission.

Of the eight people on board, five were killed, two survived, and one was missing, officials said. The aircraft went down Monday afternoon near Galveston, about 50 miles southeast of Houston.

Galveston County sheriff's deputies responded to the report of a plane crash near the base of the causeway, according to a Facebook post. Sheriff's office personnel, including a dive team, crime scene unit, drone unit and patrol, assisted at the scene.