Rescue workers are using remote cameras to search inside a tour boat that sank off the northern Japanese prefecture of Hokkaido.

The "KAZU I" went missing off the Shiretoko Peninsula during a cruise on April 23. Twenty-four passengers and two crew members were on board.

Fourteen people have been found but all were confirmed dead. Search operations are underway to locate the other 12.

The submerged vessel lies too deep for rescue divers to reach. Coast guard and Maritime Self-Defense Force personnel are using underwater cameras to see if they can locate anyone trapped in the boat.

Footage has revealed the door to a cabin is open. The rescuers are trying to find a way to get the camera through the doorway, so they can look inside.

People are offering flowers for the victims a week after the incident.

Local fishing vessels and tour boats are also continuing to aid search efforts.