The Japan Coast Guard says it has spotted four people believed to have been on board a tour boat that ran into trouble in waters off the northern prefecture of Hokkaido.
Their conditions are unknown. Twenty-six people were on board the ship.

Coast Guard officers say the boat sent a distress call on Saturday afternoon during its tour around the Shiretoko Peninsula, a UNESCO World Heritage site.

They say 24 passengers, including two children, and two crewmembers were on board the ship. All of them were reported to be wearing life vests.

The crew relayed information that the ship was taking on water and listing at an angle of about 30 degrees and that it could not move on its own as its engine had stopped.

The Coast Guard sent six patrol ships and four planes to look for the boat "KAZU I." The Air Self-Defense Force also dispatched a search-and-rescue aircraft.

Meteorological Agency officials say waves in the area were up to three meters high at the time the boat issued the distress call.

The Coast Guard says the boat ran aground last June right after leaving the same port. None of the 23 people on board were injured and the ship was able to return to the port.