Navy SEAL candidate dies, another hospitalised after 'Hell Week' training

A Navy SEAL candidate died on Friday and another was hospitalised in San Diego after completing a training phase known as 'Hell Week.'

The Navy said in a statement on Sunday that Kyle Mullen, 24, of Manalapan, New Jersey, died at a California hospital following the training.

The cause of Mr Mullen's death is currently unknown and is under investigation, according to the statement.

LIVE UPDATES: Around 1700 ADF personnel to assist in aged care facilities

The injured candidate is in a stable condition at Naval Medical Centre San Diego.

Neither Mr Mullen nor the injured sailor, who has not been named, were "actively" training when they began suffering symptoms, according to the Navy.

"We extend our deepest sympathies to Seaman Mullen's family for their loss," said Rear Admiral H W Howard III, the commander of Naval Special Warfare Command, in a statement.

"We are extending every form of support we can to the Mullen family and Kyle's ... classmates."

NBC first reported on the incident.

READ MORE: Aussie property market correction looms, big bank predicts

They began suffering symptoms "several hours" after the sailors' Basic Underwater Demolition SEAL (BUD/S) class had completed Hell Week and were taken for emergency medical care, according to a statement.

Hell Week is "part of the first phase of the Navy SEAL assessment and selection pathway," according to Naval Special Warfare Command.

It is considered the pinnacle of training for Navy SEALS and consists of five days in which trainees are constantly cold, hungry, sleep-deprived and wet.