At least 19 houses collapsed after an earthquake measuring 6.0 on the Richter scale struck southern Japan on Thursday. The region was hit by multiple aftershocks, according to reports, but there wasn't any tsunami warning. There were also no problems reported at nearby nuclear power plants. The epicentre of the quake, which occurred at 9.26 pm local time, was 11 km south of Kumamoto city, the United States Geological Survey said.

The strong tremors brought down several buildings, Reuters reported. Government official Yoshihide Suga said the extent of damage was unclear because it was dark. Police said it fears people are trapped under the debris, while at least 45 people were admitted to the Japanese Red Cross Kumamoto Hospital, five of whom had sustained serious injuries, according to The Associated Press.

A fire had broken out in Mashiki town, located near the epicentre, reported Japanese television channel NHK. Operations of some high-speed trains were suspended as a precaution. The USGS first said the magnitude of the quake was 6.2, but it revised it later. However, NHK said the earthquake measured 6.4.

The temblor was reportedly the strongest since the 9.0-magnitude quake that struck in 2011, triggering a powerful tsunami that left nearly 16,000 people dead and more than two lakh people displaced.