Japanese PM Takaichi says it’s a ‘race against time’ to rescue those still trapped in the mall and others affected by the quake.

Thousands of shoppers and store employees, quickly evacuated by staff after a magnitude 7.1 earthquake, watched in horror as an explosion ripped through Kumamoto’s Aeon mall, exposing steel beams and catapulting debris across the parking lot.

Workers in and around one of southern Japan’s largest shopping centres described being thrown to the ground and enveloped in a disorienting cloud of dust by the explosion that followed the massive quake on Tuesday.

“I thought a bomb had gone off,” Takateru Sonoda, 41, who runs a combined hair salon and cafe near the mall, told news agency Jiji Press.

“There were people calling on others to evacuate, and sirens were ringing out. Nearby roads were gridlocked; it was a state of panic.”

First responders, initially fearful of entering the wreckage, hauled eight people from the partially collapsed site early on Wednesday, three dead among them.

The status of three shop workers remains unknown, Aeon said, adding that it was investigating a possible gas leak as a potential cause for the explosion.

Japanese Prime Minister Sanae Takaichi said on Wednesday that it was a “race against time” to rescue those trapped in the mall and others affected by the quake.

About 170 soldiers have been deployed to help with rescue operations at the site.

All 25 cats left behind in a cat cafe during the hasty evacuation were rescued on Wednesday, the cafe owner said in a social media post, thanking rescue workers.

Aeon mall had just reopened last month, a new and improved shopping and entertainment complex, after its recovery from another deadly tremor a decade ago.

After being badly damaged in the magnitude 7.3 Kumamoto earthquake in April 2016, the operator highlighted its seismically reinforced ceilings and overall improvements to safety and resilience.

Across the street, in a pub about 300 metres (330 yards) from the mall, Kazuya Tsurunaga was cleaning up dishes and glasses broken by the quake when he heard the deafening blast.

“A large cloud of smoke was billowing up, and because the wind happened to be blowing, and the wind direction was toward the shop, it was like volcanic ash was falling around us,” he told broadcaster TBS.

Police officers and firefighters were wary of entering the wreckage because of the risk of further collapse amid a series of aftershocks, a police official said. By the end of Tuesday, more than 100 aftershocks had occurred in Kumamoto.

Aeon President Akio Yoshida told a news conference on Wednesday that staff evacuated 3,000 shoppers within half an hour after the quake hit. But an unlucky few were inside when, 50 minutes later, the explosion occurred.

“We confirmed that all customers had been evacuated. We believed that employees had also evacuated, but it later emerged that some people had remained inside, or returned for whatever reason,” Yoshida said, adding that one survivor was found injured in a toilet.

Video shot by a police officer inside the building early on Wednesday showed large sections of the ceiling collapsed, storefronts blown open and furniture strewn across the floor.

Yoshida said the possibility the explosion was caused by gas was “very high”, but that thorough investigations were needed to understand what went wrong.

“We had not fully anticipated that an explosion of this kind could occur,” he said. “We have never had an accident like this.”