A Hellenic Navy frogman and commando on Friday fell ill during a training exercise at a base west of Athens and subsequently died.

The NCO, a member of one of the Greek navy’s “SEAL team” units, reportedly passed out and was given emergency first aid on the spot. He was immediately rushed to a nearby civilian hospital, but despite intensive treatment later passed away, a terse announcement by the Hellenic Navy general staff office read.

No cause of death or the circumstances leading to the incident were reported. An investigation has commenced into the senior petty officer’s loss, as per standard military procedure, the announcement added.