A powerful mudslide carrying a deluge of black water and debris crashed into rows of houses in a town west of Tokyo following heavy rains on Saturday, leaving at least 19 people missing, officials said.

As many as 80 homes in Atami were completely buried, according to an official with the Fire and Disaster Management Agency. The official said more people, possibly 100, could still be missing under the mudslides but warned that details were not immediately clear. The official, who spoke on condition of anonymity as is often policy at Japanese bureaucracies, stressed that aggressive rescue operations were underway to find survivors.

Public broadcaster NHK earlier gave the number of missing people at 20, but Shizuoka prefecture spokesman Takamichi Sugiyama said the prefecture confirmed at least 19, although he said the number may grow. Torrential rains have slammed parts of Japan starting earlier this week. Experts said dirt had been loosened, increasing landslide risks in a country filled with valleys and mountains.