(CNN) A 21-year-old Navy SEAL student died during his first week of basic training in California, authorities said.

Seaman James Derek Lovelace of Crestview, Florida, died Friday after taking part in underwater demolition training in Coronado, California.

Safety observers noticed he was having problems during the water familiarization exercise and pulled him out of the pool, the Navy said in a statement Tuesday.

"He was aided to the edge of the pool by instructors where he then lost consciousness. Resuscitation efforts and first aid at the scene were unsuccessful," the Navy said.

The pool exercise involves treading water and swimming in dive masks and camouflage uniform. Trainees take part in the exercise on their first week to determine their competency and confidence in the water, the Navy said.

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