A 7.1-magnitude earthquake has hit Japan's southern Kumamoto prefecture, knocking out power to thousands of homes, rupturing roads and leaving some trapped and others presumed dead inside a partially collapsed shopping mall.
Speaking to reporters from her office in Tokyo, Japanese Prime Minister Sanae Takaichi said authorities were still assessing the full extent of the damage in the area, which was devastated by a deadly quake a decade ago.
"We have already been informed that people have been injured. Power outages and fires have occurred in some areas, and there has also been damage to roads and bridges and the collapse of buildings," Takaichi said.
"I ask everyone to take action to protect themselves, including evacuating to a safe location."
About 300,000 people have been instructed to go to evacuation centres, and hundreds of soldiers have been deployed to help with rescue operations as aftershocks continued to rumble in the area, on Japan's southwestern island of Kyushu.
About 20 to 30 workers at the prefecture's largest shopping mall were unaccounted for after it was rocked by an explosion in the aftermath of the quake, NHK said.
Fire services earlier said several people were trapped inside.
Local news outlets quoted police saying several had died or were presumed to have perished in the incident, although Reuters could not immediately confirm the reports.
One side of the mall, which houses about 200 stores, was torn away, exposing steel beams and strewing debris across a vast parking lot, footage showed.
Several ambulances and fire engines were parked outside as rescue teams searched for survivors.
A spokesperson for mall operator Aeon said customers and employees were led out right after the initial quake and that the exact cause of the ensuing explosion was unclear.
Authorities are investigating a possible gas explosion, broadcaster NTV reported.
Kazuya Tsurunaga told TBS he was stunned by the blast while cleaning up dishes broken by the earthquake inside a pub about 300 metres from the Aeon mall.
"It was a huge impact," he said.
"A large cloud of smoke billowed up, and because the wind happened to be blowing and the wind direction was towards the shop, the area around us was in a state like volcanic ash was falling."
Multiple people were also unaccounted for after a chimney collapsed at a Nippon Paper Industries factory, broadcaster NHK reported, while two hospitals were each reported to be treating more than 50 people, some in serious condition.
Several passengers aboard high-speed trains at the time of the quake were also injured, operators said.
Authorities said they were responding to multiple incidents where buildings had partially collapsed or had caught fire.
One person died in one such collapse in a town near the epicentre, TV Asahi reported.
Some roads were also badly damaged, with large cracks splintering major highways, snarling traffic.
Rail services were suspended and flights grounded.
The quake’s epicentre was 20km south of Kumamoto city, central Kyushu's largest city with a population of about 700,000.
Residents in the areas that felt the biggest tremors must be on alert for further strong quakes for about a week, as well as for the risk of landslides, an official for the Japan Meteorological Agency said.
About 100 small aftershocks have hit Kumamoto already since the initial jolt, JMA said.
With thousands of homes still without power as night fell, authorities warned residents about the risk of heat stroke as temperatures were set to hit 34C on Wednesday.
