Authorities in Japan say at least 19 people are missing after a powerful mudslide caused by heavy rains swept away rows of houses in a town west of Tokyo.

A spokesman says dozens of homes may have been buried in Atami, known for its hot springs.

Defense forces are joining firefighters and police in the rescue operation, and evacuation warnings have been issued for a wide area.

Footage Saturday showed a powerful, black mudslide slither down a mountain, knocking over and crushing houses and sweeping away cars in its path.

Helpless neighbors watched in horror, some recording on their phones.