A veteran Greek diver specializing in locating sunken ships announced Wednesday that he has found a British submarine that disappeared during a World War II mission in 1942.

Kostas Thoctarides told state news agency ANA his team had located the wreck of HMS Triumph at a depth of 670 feet at an undisclosed location in the Aegean Sea.

The search for the submarine began in 1998 and was "the hardest mission I have ever undertaken in my life," Thoctarides said in a Facebook post. He also posted video and images of the shipwreck, showing the wooden steering wheel, compass and cannon.

"The plug of the right torpedo, located at the tower height, has opened and the MK VIII torpedo is halfway out of the submarine!" Thoctarides wrote.

Research in archives in the UK, Germany, Italy and Greece helped to unlock the submarine's final resting place, he added.

The 84-meter T-class submarine was launched in 1938 and carried out twenty missions, including attacks against Axis ships, landing British commandos and rescuing Allied soldiers.

Thoctarides -- who in 1997 located the hulk of HMS Perseus, a British submarine that sank in 1941 -- said the Triumph was last sighted by an Italian pilot near Cape Sounion near Athens.

The last attack by the vessel is believed to have been against an Axis cement freighter.

It was officially declared missing with 64 people on board in January 1942.

Thoctarides told ANA that the submarine's periscopes and hatches were down, indicating that it was in a deep dive during its final moments.

It appears to have sunk due to a powerful explosion in the fore section but the cause of the blast is still unclear, he said.

Thoctarides said recently his team discovered several torpedoes of the same type used by the submarine not too far from the shipwreck.

"This fact leads us to believe that the Triumph fired more than one torpedo" during its final mission, he wrote.

Thoctarides said the HMS Triumph marked the fifth submarine he has found off the coast of Greece. Last year, he announced that his team had found the wreckage of the Jantina, an Italian submarine that sank on July 5, 1941, with 48 crewmembers aboard after being hit by torpedoes fired by the British sub HMS Torbay in the Aegean Sea.

The discovery of Triumph comes less than two months after a team of explorers announced it found a sunken Japanese ship that was torpedoed off the coast of the Philippines in 1942, resulting in Australia's largest maritime wartime loss with a total of 1,080 lives.

In:
• Shipwreck
• World War II
• Greece