Members of the Special Response Team (SRT) aboard the aircraft carrier USS Nimitz stand guard on the flight deck.
U.S. Navy Special Response Teams are specially-trained Naval Security Force (Military Police) personnel, typically Master-At-Arms, stationed with a given Naval installation / vessel.
As with USMC, Army and USAF SRTs, Navy Special Response Teams / Special Response Forces are special weapons and tactics (SWAT) teams tasked with responding to crisis situations such as active shooters, hostage taking, barricaded suspects and with providing additional security during high profile events.