TOKYO — At least nine people were killed and 761 injured by a magnitude-6.5 earthquake Thursday night that knocked down houses and buckled roads in southern Japan, the government’s chief spokesman said.

Yoshihide Suga said he would visit the area Friday to assess the damage. He said some 1,600 soldiers had been deployed, and TV reports showed some delivering blankets and adult diapers to the thousands of people who took shelter because their homes were wrecked or unsafe.

The worst damage was in the town of Mashiki, 9 miles east of Kumamoto city on the island of Kyushu, said a Kumamoto prefecture disaster management official. The area is 800 miles southwest of Tokyo.

Suga said 44 of those injured were seriously hurt.

The quake struck at 9:26 p.m. at a depth of 7 miles near Kumamoto city on the island of Kyushu, the Japan Meteorological Agency said. There was no tsunami risk.

Suga said at least 19 houses collapsed, and hundreds of calls came in reporting building damage and people buried under debris or trapped inside.Rescue operations were repeatedly disrupted by aftershocks.

“There was a ka-boom and the whole house shook violently sideways,” Takahiko Morita, a Mashiki resident told 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.

Local broadcasters were urging residents to check on elderly people who might not be able to escape their homes unaided.

Dozens of people evacuated their homes and gathered outside Mashiki town hall, sitting on tarps well after midnight.

Suga said there were no abnormalities at nuclear facilities. The epicenter was 74 miles northeast of Kyushu Electric Power Co.’s Sendai nuclear plant, the only one operating in the country.