Titanic submarine: Desperate search for craft missing with five onboard

Rory Golden, the first Irishman to dive to the Titanic wreck, has taken to social media to assure people of his safety.

This image provided by the Woods Hole Oceanographic Institution shows the deck of Titanic 12,500 feet below the surface of the ocean, 400 miles (640 kilometers) off the coast of Newfoundland, Canada in 1986. File picture: Woods Hole Oceanographic Institution via AP

Search and rescue teams were racing against time on Monday to find a tourist submarine with prominent maritime experts and explorers believed to be onboard that went missing in the North Atlantic while on a dive to the wreck of the Titanic.

Fears were rising about the fate of the vessel as military and coast guard aircraft stepped up efforts later on Monday.