The long-sought wreckage of the USS Samuel B. Roberts, a World War II U.S. Navy destroyer escort that sank in the Western Pacific Ocean nearly 78 years ago, has been found off the Philippines, explorers have announced.

The vessel, now broken in two, lies at a depth of around four miles, the deepest shipwreck yet discovered. That's deeper than Mount Kilimanjaro is tall, or 18 times the height of the Empire State Building.

The wreckage was identified and surveyed by American explorer Victor Vescovo, founder and sub pilot of Dallas-based Caladan Oceanic Expeditions, alongside Britain-based EYOS Expeditions.

"It was an extraordinary honor to locate this incredibly famous ship, and by doing so have the chance to retell her story of heroism and duty to those who may not know of the ship and her crew's sacrifice," Vescovo said in a statement.

"Resting at 6,895 meters, it is now the deepest shipwreck ever located and surveyed," Vescovo later tweeted. He said he was joined on the expedition by a sonar specialist, Jeremie Morizet.

"It appears her bow hit the seafloor with some force, causing some buckling. Her stern also separated about 5 meters on impact, but the whole wreck was together," he added. "This small ship took on the finest of the Japanese Navy, fighting them to the end."

Photos shared online by Vescovo show the ship's bow and fallen mast engulfed in blue water and indicate where the vessel was likely hit by a battleship round during the Battle off Samar, the final engagement of the larger Battle of Leyte Gulf in 1944.

The Sammy B took part in the large naval battle in October 1944, which involved an improbable victory in the waters surrounding the Philippines. Several small U.S. destroyers and destroyer escorts, outnumbered, engaged the Imperial Japanese Navy, including its huge Yamato battleship, forcing it into retreat.

But after expending virtually all her ammunition, the Sammy B was hit by a Japanese battleship and sunk, along with other U.S. vessels, including the USS Johnston.

The USS Johnston, which previously held the record for the deepest shipwreck found at 6,469 meters below sea level, was surveyed by Vescovo and his team in March 2021. Vescovo, a former U.S. Navy reserve intelligence officer, has also made three dives to the Titanic.

The Sammy B, taken into battle by Lt. Cmdr. Robert W. Copeland, possessed fewer guns and torpedoes than her counterparts, according to Caladan. Eighty-nine of its 224 crew were killed.

"This site is a hallowed war grave," said retired Rear Adm. Sam Cox, head of the Naval History and Heritage Command in Washington. All data related to the dive, including sonar maps, video and photographs, will be donated to the U.S. Navy, the team said.

The Caladan Oceanic and EYOS group conducted six dives over eight days searching for shipwrecks from June 17 until Friday. They initially located debris that was positively identified as belonging to the Sammy B before uncovering the entire wreck.

"Using a combination of detective work and innovative technology, everyone has pulled together to reveal the final resting place of this tenacious ship," expedition leader Kelvin Murray of EYOS said in a statement.

"It's been a challenging, thrilling and poignant expedition," he said. "We are all proud of what has been achieved and humbled by what we witnessed."

The group is now on its way to Guam to begin further expeditions in the Western Pacific.