A powerful earthquake with a magnitude of 6.5 knocked over houses in southern Japan on Thursday evening, and police said people may be trapped underneath.
Japanese Red Cross Kumamoto Hospital said it has admitted or treated 45 people, including five with serious injuries.
The quake struck at 9:26 p.m. at a depth of 11 kilometers (7 miles) near Kumamoto city on the island of Kyushu, the Japan Meteorological Agency said. There was no tsunami risk.
"The shaking was so violent I couldn't stand still," said Hironobu Kosaki, a Kumamoto Prefectural Police night-duty official.
He said they had received reports of collapsed houses and people possibly trapped inside.
Japan's Chief Cabinet Secretary Yoshihide Suga said at least 19 houses had collapsed. "Because of the night darkness, the extent of damage is still unclear," he said.
The meteorological agency said the shaking was most severe in the town of Mashiki, 15 kilometers (9 miles) east of Kumamoto city and about 1,300 kilometers (800 miles) southwest of Tokyo.
"There was a ka-boom and the whole house shook violently sideways," Takahiko Morita, a Mashiki resident said in a telephone interview with Japanese broadcaster NHK. "Furniture and bookshelves fell down, and books were all over the floor."
Morita said some houses and walls collapsed in his neighborhood, and water supply had been cut off.
Suga said there no abnormalities at nearby nuclear facilities. The epicenter was 120 kilometers (74 miles) northeast of the Sendai nuclear plant, the only one operating in the country.
NHK showed Mashiki town hall in the dark after having lost power. Other footage showed rubble on the road, shards of glass and broken windows, and fire breaking out in some places, with firefighters battling an orange blaze.
Keisukei Urata, an official in nearby Uki city who was driving home when the quake struck, told NHK that parts of the ceiling at Uki City Hall collapsed, windows broke and cabinets fell to the ground.
Kasumi Nakamura, an official in the village of Nishihara, said that the rattling started modestly and grew violent, lasting about 30 seconds.
"Papers, files, flower vases and everything fell on the floor," he told NHK.
There were multiple aftershocks, the largest one with a preliminary magnitude of 6.4 shortly after midnight, according to the Japan Meteorological Agency.
The U.S. Geological Survey measured the initial quake's preliminary magnitude at 6.2.
Footage from an NHK bureau in the area showed books, files and papers raining down to the floor. One employee appeared to have fallen off a chair, while others slid under their desks to protect their heads.