YATSUSHIRO, Japan (AP) — Thousands of survivors of a powerful earthquake in southwestern Japan spent Friday in crowded shelters or sleeping in cars as they faced shortages of water and fuel and punishing summer temperatures that stoked fears of heat-related illness.

The death toll rose to 34, the Kumamoto prefectural government said, as rescuers raced to find those still missing after the quake triggered a mall explosion, toppled a factory chimney and flattened homes.

READ MORE: Hope dwindles for rescue after southwestern Japan earthquake as death toll climbs to 25

Japanese Prime Minister Sanae Takaichi stressed that authorities must secure water supplies by doing "whatever it takes" and called for close coordination with the military and other relevant agencies. The earthquake left thousands of homes without power, but electricity was fully restored by Friday evening. The local power company also said there were no immediate reports of remaining outages.

The magnitude 7.1 earthquake hit Japan's southern main island of Kyushu on Tuesday. As search operations entered a fourth day, it wasn't known how many people remained missing.