KUMAMOTO, Japan — Soldiers and emergency workers combed through a badly damaged shopping mall and collapsed houses looking for trapped survivors Wednesday after a powerful earthquake that killed at least 18 people, including a foreigner, in southwestern Japan.

The magnitude 7.1 earthquake that hit a day earlier in the Kumamoto area on the southern main island of Kyushu also left at least 62 people injured, six of them seriously, the prefectural government said. The tally has been steadily growing, fanning fears it may continue to rise.

The sweltering weather heightened worries about the survivors as rescuers braved the heat. It remained unclear how many people might still be missing.

Some of the most serious damage was at the Aeon Mall shopping center in Kashima city, which was bustling with thousands of people when the quake happened. The company said some 3,000 customers were evacuated to a parking lot before a gas explosion happened in another part of the mall, where some people were still working.

The mall’s second floor collapsed, trapping people. Witnesses said the explosion shook the area as much as the quake.

Three people remained missing, while four deaths were confirmed at the mall site, according to Aeon President Akio Yoshida.

“We take it seriously that an explosion happened and precious lives were lost,” Yoshida told a news conference in Kumamoto, where he bowed deeply along with two other executives.

Japanese media footage of the mall showed that part of the ceiling had caved in, and metal pieces and other debris were scattered about as helmeted and masked rescue workers searched the area.

Kiyoshi Matsunaga, 74, who lives in the mall’s neighborhood and was at a supermarket just a few blocks away, said he thought he was going to die.

He stopped in his tracks when the shaking began while he was pushing his cart toward a cash register. Things scattered from the shelves. He could not move, he recalled.

“I was frightened,” he said.

In nearby Yatsushino, a chimney collapse at a Nippon Paper Industries factory killed five people while seven others were rescued from the debris, according to the Kumamoto prefectural government disaster team.

Four people were still believed to be trapped there, it said.

In the first reported death of a foreign national, a Vietnamese technical intern was killed after a crane fell on him at a factory where he worked, according to the Vietnamese government. He had arrived in Japan in January. Seven other Vietnamese technical interns at the factory evacuated safely

Separately, a Vietnamese woman married to one of the workers was injured when a wall collapsed and was being treated at a hospital.

Nearly 34,900 homes were still without electricity and some 15,000 homes without running water, Kumamoto officials said. More than 8,800 people left their homes to stay in over 400 shelters, where power sources were being added to provide air conditioning.

Aerial police footage showed some homes in residential areas were completely flattened, including a few that crumbled into a nearby river.

Japan’s Self Defense Forces joined rescue workers in the search and rescue operations. Hundreds of professionals were helping with the effort, including firefighters from Taiwan.

“There are people who are still waiting to be rescued, and it’s a race against time,” Prime Minister Sanae Takaichi said. “We will go all out to find and rescue as many people as we can.”

Takaichi said the federal government was preparing to deliver food and other necessities to hard-hit areas. She also offered her condolences to the victims and sympathy to their relatives, while urging those affected by the quake to take care of themselves under the hot weather.

Bullet train services remained suspended. Although operations at Aso Kumamoto Airport resumed Wednesday, some airlines canceled flights as a precautionary measure.

Kumamoto was hit with a deadly quake in 2016 that killed at least 50 people. Japan is one of the most quake-prone nations in the world.

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Associated Press writers Yuri Kageyama in Tokyo and Aniruddha Ghosal in Hanoi, Vietnam contributed to this report.