The ship, which went missing Saturday many hours after embarking on a sightseeing excursion, has yet to be located; one youngster is among the 11 people who died.

As rescue attempts to recover the boat and its missing passengers increased on Monday, inquiries into what caused the loss of a Japanese tour boat off the country’s northern coast began, with the confirmed death toll growing to 11.

The ship, the “Kazu I,” departed dock on Saturday carrying 24 guests, including two children, and two crew members on one of the famed sightseeing tours that the northern Shiretoko peninsula is known for. Only a few orange flotation devices carrying its name have been discovered floating throughout the difficult coastline’s rocky region.

One of the victims is a youngster.

On Monday, the search was continued with the use of planes and patrol boats, with local fishing boats from the port of Utoro also being deployed, according to media reports. Searchers also hiked along the shoreline’s rocky cliffs.

On Sunday, officials from the transport ministry travelled to the scene to coordinate activities, and Transport Minister Tetsuo Saito also paid a visit, urging everyone to do everything necessary to figure out what went wrong and prevent it from happening again.

On Monday, a transport ministry investigator told reporters at the scene, “Our mission is to find out precisely what happened.”

Waves were high in the area on Saturday, according to media sources, and fishing boats that left early in the morning immediately returned to port due to the rough seas.