At least 10 people were confirmed dead Sunday after a sightseeing boat sank in frigid waters off Japan's northeast, the coast guard said, with the search continuing for 16 others still missing.
"We have confirmed the deaths of all 10 people" who have so far been retrieved, a coastguard spokesman told AFP.
In a statement, the coast guard added that those found so far had been identified as seven men and three women.
The Kazu I sightseeing boat sent a distress signal on Saturday afternoon after it began taking on water off the remote northeastern tip of Japan's Hokkaido region.
A search-and-rescue operation began immediately, but hopes soon began to fade for the 26 people on board, including two children and two crew, because of the cold temperatures in the region.
The boat had set out on Saturday morning on a sightseeing cruise of the sort that is popular in the Shiretoko Peninsula, a designated UNESCO World Heritage site for its pristine natural environment and diverse wildlife.
The tour went ahead despite high winds and waves that reportedly prompted even some local fishing boats to return to shore to avoid the worsening conditions.
"It was clear that the conditions at sea would worsen, so I told them not to go," a local tour boat operator told NHK. "But they did (went) anyway. I told the captain not to."
The boat issued a distress call at around 1:15pm (0415GMT) on Saturday, with coast guard helicopters and vessels arriving in the area several hours later.
By nightfall though, as the air temperature dropped to around zero degrees Celsius, there was no sign of either the boat or those aboard, though the search continued overnight with infrared and thermal equipment.
Local police and Japan's Self Defense Forces have joined the rescue operation, and the first four people from the boat were located early on Sunday, with six more being retrieved in the following hours.
Some were found in the water, while others were spotted along the rugged shoreline, where images from national broadcaster NHK showed rescue workers combing the coast as waves crashed into the shore.
- Icy shores -
Images released by the coast guard showed rescuers crouched in a crevasse along the rocky shoreline inspecting an area, as well as items clearly marked Kazu I washed up on a beach, with ice still visible on the shore.
Those rescued so far have been taken to hospitals, and NHK showed images of at least one person being transferred from a helicopter to an ambulance with officials holding up a blanket to shield their identity.
The Shiretoko Peninsula was designated a UNESCO world heritage site in 2005. It is well known for its unique wildlife, including the endangered Steller sea lion, as well as migratory birds and brown bears.
Sightseeing boat trips in the area are popular for visitors hoping to spot whales, birds and other wildlife, as well as drift ice in the winter.
Japan's borders remain closed to tourists because of Covid-19 rules, so sightseeing in the country is effectively limited to residents and Japanese citizens.
The Kazu I ran aground in shallow water in June last year, becoming stranded with 21 passengers and two crew members on board, according to Japanese media.
The boat was able to leave the shallows on its own and returned to the port, but police investigated its captain for endangering traffic by negligence in the conduct of business.
Japan's coastguard has been involved in a variety of search and rescue missions around the archipelago, including the successful discovery last November of a 69-year-old man who spent 22 hours drifting in open water off southwestern Kagoshima.
In September 2020, a cargo ship with 43 crew onboard sunk after being caught in a typhoon off Japan's southwest coast.
Two survivors were rescued, while a third crew member was found unresponsive and declared dead. The search operation was called off a week later.