More than 100 aftershocks hit Japan after powerful quake that killed 13

Japan's south-western Kyushu region has had more than 100 aftershocks since it was struck on Tuesday by a powerful earthquake which left at least 13 people dead.

Many others were said to be in cardiac arrest - a term often used in preliminary reports in Japan before a death is officially confirmed.

In searing heat, rescue crews are digging through the rubble at a paper factory and a shopping mall in Kumamoto prefecture, looking for trapped survivors. The mall suffered an explosion in the hour after the quake struck.

Japanese Prime Minister Sanae Takaichi warned it was "truly a race against time" to rescue those trapped. Thousands are in evacuation centres and many are without power.

The Japan Meteorological Agency (JMA) is urging residents to be alert for the possibility of strong aftershocks, public broadcaster NHK reported.

"For the next week or so, especially the next two to three days, we would like people to watch out for potential earthquakes with a maximum seismic intensity of 7," a JMA official said.

Tuesday's quake hit the Kumamoto prefecture on Kyushu island at 16:27 local time (07:27 GMT).

One of the worst-hit buildings was the Aeon Mall in Kashima, where a portion of the second floor collapsed.

Footage of the shopping centre showed white smoke rising as people ran into the car park. Large parts of the centre's exterior were blown off, exposing the steel beams underneath.

Three people remain unaccounted for as rescuers search the rubble.