SAN DIEGO — Richard Lyon, the first Navy SEAL to rise to the rank of admiral, has died at 93.

Lyon served four decades in the Navy, including World War II and the Korean War, and was among the first U.S. troops to enter Japan after the atomic bomb was dropped.

He went on to work as a Scout intelligence officer in northern China and later served in Korea.

Rear Adm. Tim Szymanski, commander of the Naval Special Warfare Command, called Lyon a legend who was honored with the title “Bullfrog” for being the oldest-serving SEAL.