Five people were killed after a small plane belonging to the Mexican Navy crashed off the coast of Galveston, Texas, on Monday, officials said in a statement.

Eight people were on board the small plane when it crashed. Out of the eight, five people died, two people are alive and one person is still missing, the Mexican Navy said.

The aircraft that crashed was conducting a “humanitarian mission focused on specialized medical transport,” the Mexican Navy said.

The crash occurred after 3 p.m. on Monday near Galveston, along the Texas coast, approximately 50 miles southeast of Houston. 

The cause of the crash is under investigation.

This is a developing story. Please check back for updates.