A tour boat with 24 passengers, including two children, and two crew members on board went missing Saturday while on a tour around the scenic Shiretoko Peninsula on Hokkaido, the Japan Coast Guard said.

The boat Kazu I reported to the coast guard it was taking on water around 1:15 p.m., and then told its operator that it was tilting 30 degrees around 3 p.m. before losing contact, the coast guard said.

The coast guard, which dispatched a helicopter and patrol boats to the site near the peninsula, said it had not found the boat nor the people on board as of 9 p.m., adding that their fate remains unknown.