The five people aboard a missing submersible died in a “catastrophic implosion,” a US Coast Guard official said on Thursday, bringing a grim end to the international search for the vessel that was lost during a deep-sea voyage to the wreck of the Titanic.

“These men were true explorers who shared a distinct spirit of adventure, and a deep passion for exploring and protecting the world’s oceans,” OceanGate Expeditions, the US-based company that operated the Titan submersible, said in a statement. “Our hearts are with these five souls and every member of their families during this tragic time.”

An unmanned robot deployed from a Canadian ship discovered the wreckage of the Titan on Thursday morning about 1,600 feet (488 meters) from the bow of the century-old wreck, 2-1/2 miles (4 km) below the surface in a remote area of the North Atlantic, US Coast Guard Rear Admiral John Mauger said at a press conference.

“The debris field here is consistent with a catastrophic implosion of the vehicle,” Mauger said.

Debris discovered on the ocean floor suggested the missing submersible near the wreck of the Titanic suffered a “catastrophic loss” of pressure, the US Coast Guard said.

“On behalf of the United States Coast Guard and the entire unified command, I offer my deepest condolences to the families,” he added.

British foreign minister James Cleverly said the government was supporting the families of those lost on board the Titan submersible, expressing his condolences in a post on Twitter.

“Tragic news that those on the Titan submersible, including three British citizens, have been lost following an international search operation,” he said.

“The UK government is closely supporting the families affected and expresses our deepest condolences,” added Cleverly.

Pakistan also has offered the country’s condolences to the Dawood family after the father-and-son explorers were among five killed when the Titan submersible imploded deep in the North Atlantic waters during a trip to the Titanic’s wreckage.

Pakistani nationals Shahzada Dawood and his son Suleman were aboard the Titan when it went missing Sunday.

“Our deepest condolences to the Dawood family and the family of other passengers on the sad news about the fate of Titanic submersible in the North Atlantic,” Pakistan’s Foreign Ministry wrote on Twitter. “We appreciate the multinational efforts over the last several days in search of the vessel.”

The White House also offered its condolences to the families mourning the five people killed aboard the Titan submersible.

“Our hearts go out to the families and loved ones of those who lost their lives on the Titan,” the White House said in a statement. “They have been through a harrowing ordeal over the past few days, and we are keeping them in our thoughts and prayers.”

The statement also thanked the searchers, including the Coast Guard, involved in the international effort to find the submersible.

“This has been a testament to the skill and professionalism that the men and women who serve our nation continue to demonstrate every single day,” the statement said.