A small Mexican Navy plane transporting a young medical patient and seven others crashed Monday near Galveston, killing at least five people and setting off a search in the waters off the Texas coast, officials said.

Four of the people aboard were Navy officers, and four were civilians, including a child, Mexico`s Navy said in a statement to The Associated Press. It was not immediately clear which of them died. Two of the people aboard were members of the Michou and Mau Foundation, which is a nonprofit that provides aid to Mexican children who have suffered severe burns.