An earthquake registering a magnitude of 7.3 struck southern Japan early Saturday, killing at least 29 people and injuring 1,500 less than 24 hours after a quake hit the same region.

Chief Cabinet Secretary Yoshihide Suga said that of the 1,500 injured, 80 were in a serious condition. Nearly 70,000 have left their homes, he said.

Japanese media reported that nearly 200,000 homes were without electricity. Drinking water systems had also failed in the area.

Japanese broadcaster NHK said a number of calls were coming in from residents reporting people trapped inside houses and buildings and that hundreds were being treated in hospitals. Authorities warned of extensive damage over a broad area.

The quake struck Japan's Kumamoto region at 1:25 a.m. local time (16:25 UTC Friday) with several aftershocks soon following. Japan's Meteorological Agency posted a tsunami advisory for a wave of up to one meter (around three feet) in height along the coast of Kumamoto, but the warning was shortly lifted.

The epicenter of the quake was near the city of Kumamoto and measured at a shallow depth of 10 kilometers (6.2 miles), the U.S. Geological Survey said. The quake knocked out power to the entire city of 730,000.

Chief Cabinet Secretary Yoshihide Suga said more than 300 calls came in to the Kumamoto police and another 100 to police in nearby Oita, seeking aid and reporting people trapped or buried under debris.

Japan's Nuclear Regulation Authority said it reported no damage or irregularities at the Sendai nuclear plant as a result of the latest quake.

Prime Minister Shinzo Abe warned of "extensive" damage from the quake and urged rescue workers to do their utmost to help those trapped in the rubble. He said the government was making every effort to determine the extent of the damage, carry out rescue and recovery and to get accurate information to citizens.

"It's possible that there may be damage over a wide area," Abe said.

Two days, two quakes

Late Thursday, a weaker 6.5 magnitude quake struck the nearby town of Mashiki, killing nine people and injuring hundreds more. The new quake appears to have damaged areas farther to the northeast.

Experts warned the two quakes could be linked as several aftershocks struck the region later on Saturday, and the Meteorological Agency warned of more.

"Thursday's quake might have been a foreshock of this one," Shinji Toda, a professor at Tohoku University, told NHK.

Japan is on the earthquake-prone "ring of fire" around the Pacific Ocean. In March 2011, a magnitude 9 quake struck to the north of Tokyo, touching off a massive tsunami and triggering nuclear meltdowns at Fukushima. Nearly 20,000 people were killed in the tsunami.

bw/cmk (Reuters, AP, AFP)