Several people are trapped inside a shopping mall after a strong earthquake hit southwestern Japan, authorities say.

Some reports say there was an explosion at the Aeon Mall in Kumamoto, following the 7.1 magnitude earthquake that injured several people.

The earthquake struck inland on the island of Kyushu at 16:27 local time (07:27 GMT), and more than 150,000 people were asked to move to evacuation shelters. There was a brief tsunami warning that was lifted after an hour.

Japan is one of the most earthquake-prone countries, experiencing around 1,500 a year.

The weather agency has warned of strong aftershocks given the shallow epicenter: 10 kilometers (six miles). Images broadcast by national broadcaster NHK already show cracked roads and bridges and several buildings on fire.

“We are still assessing the extent of injuries and property damage, but I have been informed that there have already been several injuries,” Prime Minister Sanae Takaichi said Tuesday.