Rescue efforts were underway Wednesday morning at Aeon Mall Kumamoto in Kashima Town where people are feared trapped following Tuesday's earthquake. Photo courtesy of Japan's Fire and Disaster management Agency/X

July 29 (UPI) -- The death toll from a strong earthquake that struck southwestern Japan climbed to 13 on Wednesday morning, Prime Minister Sanae Takaichi said, as she warned that "time is of the essence" as efforts were underway rescue people who remained trapped under rubble.

The magnitude-7.1 earthquake struck at about 4:27 p.m. local time Tuesday in Kumamoto Prefecture on Kyushu, Japan's southwestern island. A tsunami advisory was issued for the Ariake and Yatsushiro seas shortly after the earthquake but was lifted within two hours.

Images posted online by various emergency services showed widespread destruction. The Nippon Paper Yatsushiro Mill in Yatsushiro City and Aeon Mall Kumamoto in Kashima Town were the site of two of the most serious rescue operations.

Japan's Fire and Disaster Management Agency said it was working other agencies at Aeon Mall on Wednesday morning where people were feared to be trapped.