The US Navy has launched multiple Trident II D5 ballistic missiles off the coast of Florida and into the Atlantic in the latest test of a system that can deliver thermonuclear warheads thousands of miles away.

An Ohio-class submarine launched the unarmed weapons from a submerged position during tests, marking the 197th consecutive successful test flight of the Trident II system.

One evening saw the skies light up as far away as Puerto Rico, as mariners and airmen were informed of the operation well in advance in order to establish safety zones along the missile's path.

Johnny R Wolfe, the director of the Navy's Strategic Systems Programs, said: "Our nation's submarine launched ballistic missile system has been a critical component of our national security since the 1960s, and these launches continue to demonstrate the credibility and reliability of our strategic deterrence capabilities."

The Trident II has been in operation since it was first introduced back in 1990 with both the US Navy and UK's Royal Navy providing the sea-based leg of the nuclear triad.

Boasting an estimated range exceeding 7,500 miles, and speeds of up to Mach 24, the missile is the brainchild of its Colorado developers Lockheed Martin Space.

It is a three-stage, solid fuel weapon that is among the strongest and most powerful the US has ever fielded, with the ability to deliver multiple independently targetable warheads with an accuracy of around 100 meters.

It can be fitted with a range of warheads including the W88 thermonuclear warhead with a yield of 475 kilotons and the much smaller W76-2 low yield option.

The British Holbrook varient of the Trident II is utilized by the UK's Vanguard-class submarines.

Director Wolfe said: "For the dedicated SSP team, maintaining our current capability and actively demonstrating through flight testing that the system is ready to respond if called upon is central to ensuring our nation’s Peace through Strength.

"The team is also pushing ahead developing the next generation strategic weapon system to ensure the sea-based deterrence capability of tomorrow."

It comes at a time of global unease amid growing threats from the likes of Russia, North Korea and China.