A powerful 7.3 magnitude earthquake rocked southern Japanese city of Kumamoto early Saturday morning, killing at least 11 people and injuring hundreds.
A tsunami warning was issued and a village in the Kumamoto prefecture was evacuated following reports of a dam collapse.
The epicentre of the new temblor was near the city of Kumamoto. It occurred at a shallow depth of 10 kms (6 miles), the U.S. Geological Survey said.
USGS said Saturday's earthquake was 22 times more powerful than the previous one on Thursday in terms of energy released. The Japan Times said the intensity of the 7.3-magnitude tremor matched that of the 1995 Great Hanshin-Awaji Earthquake.
"It's possible that there may be damage over a wide area," Prime Minister Shinzo Abe said.
The stronger tremor hit the same region a day after an earthquake killed nine people. Officials said the death toll could rise as more people were feared trapped under collapsed buildings.
The fresh tremor toppled stronger buildings and triggered a huge landslide that washed away homes and cut off a national highway in Minamiaso, the report said.
Japan Meteorological Agency said heavy rains and landslides were expected in the region and that weak structures were under threat.
A building near Tokai University's Aso Campus in Kumamoto Prefecture was among the structures that collapsed. As many as 11 people, including university students, were feared trapped under the rubble.
The initial tsunami advisory was lifted later on and officials said the nuclear installations reported no damage in the quake.
A 6.4 magnitude earthquake struck the same region on Thursday, killing nine people. Geological experts said the two tectonic events could be linked.
Japan, which lies on the seismically active "ring of fire" around the Pacific Ocean, is vulnerable to crippling earthquakes. As many as 20,000 people were killed in a tsunami triggered by an earthquake in 2011.
Bank of Japan Governor Haruhiko Kuroda said bank operations in the prefecture were normal but it was early to assess economic damage.
"We'll closely monitor the effect of the earthquake and take appropriate action, working closely with relevant authorities," Kuroda said, Reuters reported.