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.

Dozens of homes may have been buried in Atami, a town known for hot springs, said Shizuoka prefecture spokesman Takamichi Sugiyama.

Public broadcaster NHK gave the number of missing people at 20, but Sugiyama said the prefecture confirmed at least 19, although he said the number may grow.

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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.

Shizuoka Gov. Heita Kawakatsu told reporters that the Coast Guard had discovered two people who had been washed into the sea by the mudslide. Their hearts had stopped, but their deaths were not yet officially declared, he said. Other details of their identity were not released.

“I offer my deepest condolences to everyone who has suffered,” he said, adding that utmost efforts will be made to rescue lives.

Both Kawakatsu and Sugiyama said it had been raining hard in the area all morning. Self-defense forces will join firefighters and police in the rescue operation, and a minister from the national government had also arrived, they said.

Japanese media reports said Prime Minister Yoshihide Suga called an emergency meeting for his Cabinet.

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Evacuation warnings were issued for a wide area, including the so-called “Level 5,” which is the highest possible alert.

The landslides appeared to have struck multiple times, about as fast as a car. Footage 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.

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NHK TV footage showed a part of a bridge had collapsed.

Atami is a quaint seaside resort area in Shizuoka prefecture, about 100 kilometers (60 miles) southwest of Tokyo. The area that was hit by the mudslide, Izusan, includes hot springs, residential areas, shopping streets and a famous shrine.