Rescue workers search for Yumiko Yamauchi, 93, at her collapsed house in Mashiki, Kumamoto prefecture, southern Japan, Saturday, April 16, 2016. Powerful earthquakes a day apart shook southwestern Japan, trapping many beneath flattened homes and sending thousands to seek shelter in gymnasiums and hotel lobbies. Yamauchi was trapped in her bedroom as the upper floor collapsed over her in an earthquake. (AP Photo/Koji Ueda)

Two powerful earthquakes a day apart shook southwestern Japan, killing at least 29 people and injuring 1,500, as thousands of army troops and other rescuers on Saturday rushed to save scores of trapped residents before the weather turns bad.

The exact number of casualties remained unclear. Rainfall was forecast to start pounding the area soon, threatening to further complicate the relief operation and set off more mudslides in isolated rural towns, where people were waiting to be rescued in collapsed homes.

Kumamoto Prefectural official Tomoyuki Tanaka said the death toll was climbing, with the latest standing at 19 from Saturday's magnitude-7.3 quake that shook the Kumamoto region on the southwestern island of Kyushu at 1:25 a.m. On Thursday night, Kyushu was hit by a magnitude-6.5 quake that left 10 dead.

Chief Cabinet Secretary Yoshihide Suga said that 1,500 people have been injured, 80 of them seriously. Nearly 70,000 have left their homes, he said.

Japanese Prime Minister Shinzo Abe expressed concern about secondary disasters as the weather forecast showed rain and strong winds later in the day. Rainfall can set off mudslides as the soil has already been loosened by the quakes.

"Daytime today is the big test" for rescue efforts, he said. Landslides have already cut off roads and destroyed bridges, slowing down rescuers.

A sign of "SOS'" is written on the ground of an elementary school in Aso, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. Powerful earthquakes a day apart shook southwestern Japan, trapping many others beneath flattened homes and sending thousands of residents to seek refuge in gymnasiums and hotel lobbies. (Muneyuki Tomari/Kyodo News via AP)

Police received reports of 97 cases of people trapped or buried under collapsed buildings, while 10 people were caught in landslides in three municipalities in the prefecture, Kyodo News reported.

TV footage showed of a collapsed student dormitory of Tokai University, which was originally two floors, but now looked like a single story building. A witness said he heard a cry for help from the rubble. Two students were reported to have died.

In Mashiki, where people have been trapped beneath the rubble for hours, an unconscious elderly woman was dragged out from the debris of her home. Her son-in-law Tatsuhiko Sakata said 93-year-old Yumiko Yamauchi had refused to move to shelter with him after the first quake Thursday.

Rescue workers take out a teddy bear from Yumiko Yamauchi's collapsed house while searching for Yamauchi in Mashiki, Kumamoto prefecture, southern Japan, Saturday, April 16, 2016. Powerful earthquakes a day apart shook southwestern Japan, trapping many beneath flattened homes and sending thousands to seek shelter in gymnasiums and hotel lobbies. Yamauchi was trapped in her bedroom as the upper floor collapsed over her in an earthquake. (AP Photo/Koji Ueda)

"When I came to see her last night, I was asking her: 'Mother? I'm here! Do you remember me? Do you remember my face?' and she replied with a huge smile filled with joy. A kind of smile that I would never forget. And that was the last I saw of her," Sakata said.

The area has been rocked by aftershocks, including the strongest with a magnitude of 5.4 Saturday morning. The Japan Meteorological Agency said that Saturday's may be the main quake, with the earlier one a precursor. The quakes' epicenters have been relatively shallow—about 10 kilometers (6 miles)—and close to the surface, resulting in more severe shaking and damage. NHK TV said as many as eight quakes were being felt an hour in the area.

Japanese media reported that nearly 200,000 homes were without electricity. Drinking water systems had also failed in the area. TV footage showed people huddled in blankets, quietly, shoulder to shoulder, on floors of evacuation centers. An estimated 410,000 households are in need of water.

Police and firefighters try to rescue residents trapped inside an apartment which the first floor was crashed by an earthquake in Minamiaso, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. Powerful earthquakes a day apart shook southwestern Japan, trapping many beneath flattened homes and sending thousands to seek shelter in gymnasiums and hotel lobbies.(Kumamoto Nichi Nichi/Kyodo News via AP)

One massive landslide tore open a mountainside in Minamiaso village in Kunamato Prefecture all the way from the top to a highway below. Another gnawed at a highway, collapsing a house that fell down a ravine and smashed at the bottom. In another part of the village, houses were left hanging precariously at the edge of a huge hole cut open in the earth.

Suga told reporters the number of troops in the area was being raised to 20,000, while additional police and firefighters were also on the way.

He pleaded with people not to panic. "Please let's help each other and stay calm," he said in a nationally televised news conference.

Resident houses are seen destroyed after an earthquake in Mashiki, Kumamoto prefecture, southern Japan, Saturday, April 16, 2016. Powerful earthquakes a day apart shook southern Japan, trapping many beneath flattened homes and sending thousands to seek shelter in gymnasiums and hotel lobbies. (Yusuke Ogata/Kyodo News via AP)

In a hot springs resort, dozens of people trapped were picked up by military helicopters, Asahi TV reported.

Mount Aso, the largest active volcano in Japan which is located on Kyushu, erupted for the first time in a month, sending smoke rising about 100 meters (328 feet) into the air, but no damage was reported. It was not immediately clear if there's a link the seismic activity and the eruption. The 1,592 meter (5,223 foot) high mountain is about 1 ½ hour drive from the epicenter.

The historic Aso Shrine, a picturesque complex near the volcano, was seriously damaged, with a number of buildings with curved tiled roofs flattened on the ground like lopsided fans. A towering gate, known as the "cherry blossom gate" because of its grandeur especially during spring, had collapsed, totally damaged. The more than 1,700 year-old shrine is designated an "important cultural property" by the government, and has been a popular tourist spot in Kyushu.

Houses are seen destroyed after an earthquake in Mashiki, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. A powerful earthquake struck southern Japan early Saturday, barely 24 hours after a smaller quake hit the same region. (Ryosuke Uematsu/Kyodo News via AP)

The Nuclear Regulation Authority reported no abnormalities at Kyushu's Sendai nuclear plant.

NHK TV showed stones tumbled from the walls of historic Kumamoto Castle, and a wooden structure in the complex was smashed. At the Ark Hotel, east of the castle, hotel guests woke up to strong shaking and a warning siren.

A police officer stands guard in front of a house destroyed by an earthquake in Mashiki, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. A powerful earthquake struck southern Japan early Saturday, barely 24 hours after a smaller quake hit the same region. (Ryosuke Uematsu/Kyodo News via AP)

A national highway is blocked by landslide caused by an earthquake in Minamiaso, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. Powerful earthquakes a day apart shook southwestern Japan, trapping many beneath flattened homes and sending thousands to seek shelter in gymnasiums and hotel lobbies. (Hiroko Harima/Kyodo News via AP)

A man hunks down in front of a collapsed residence where his mother is being trapped after an earthquake in Mashiki, Kumamoto prefecture, southern Japan, Saturday, April 16, 2016. Powerful earthquakes a day apart shook southern Japan, trapping many beneath flattened homes and sending thousands to seek shelter in gymnasiums and hotel lobbies. (Kyodo News via AP)

An evacuee cries as she talks on a mobile phone at a park in Kumamoto, southern Japan early Saturday, April 16, 2016 after an earthquake. A powerful earthquake struck southern Japan early Saturday, barely 24 hours after a smaller quake hit the same region. (Naoya Osato/Kyodo News via AP)

A car sits on a road collapsed by an earthquake in Minamiaso, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. A powerful earthquake struck southern Japan early Saturday, barely 24 hours after a smaller quake hit the same region. (Muneyuki Tomari/Kyodo News via AP)

Vehicles sit at a parking lot damaged by an earthquake at Minamiaso in Kumamoto prefecture, southern Japan Saturday, April 16, 2016. A powerful earthquake struck southern Japan early Saturday, barely 24 hours after a smaller quake hit the same region. (Muneyuki Tomari/Kyodo News via AP)

A landslide is seen after the earthquake in Minamiaso, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. A powerful earthquake struck southern Japan early Saturday, barely 24 hours after a smaller quake hit the same region. (Kyodo News via AP)

A residents stand in front of damaged house in Mashiki, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. A powerful earthquake struck southern Japan early Saturday, barely 24 hours after a smaller quake hit the same region. (Naoya Osato/Kyodo News via AP)

Aso Shrine is destroyed by an earthquake in Aso, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. Powerful earthquakes a day apart shook southwestern Japan, trapping many others beneath flattened homes and sending thousands of residents to seek refuge in gymnasiums and hotel lobbies. (Kyodo News via AP)

Handwritten signage indicating available relief goods is held by a volunteer in Mashiki, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. Powerful earthquakes a day apart shook southwestern Japan, trapping many others beneath flattened homes and sending thousands of residents to seek refuge in gymnasiums and hotel lobbies. The signage read, from right to left, "(We have)1) drinks, 2)sweets 3)food". (Yusuke Ogata/Kyodo News via AP)

Handwritten signage indicating available relief goods are posted in Mashiki, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. Powerful earthquakes a day apart shook southwestern Japan, trapping many others beneath flattened homes and sending thousands of residents to seek refuge in gymnasiums and hotel lobbies. The signage read, from right to left and from top to bottom, "We have bread. Fresh vegetable. Rice ball. Mask. Banana. Retort pouch curry. Diaper. Carrot. Sanitary napkin. Toothbrush. Doughnut. We have instant noodles." (Naoya Osato/Kyodo News via AP)

Aso Shrine is destroyed by an earthquake in Aso, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. Powerful earthquakes a day apart shook southwestern Japan, trapping many others beneath flattened homes and sending thousands of residents to seek refuge in gymnasiums and hotel lobbies. (Kyodo News via AP)

The stonewall of Kumamoto Castle is seen damaged after the earthquake in Kumamoto city, southern Japan, Saturday, April 16, 2016. A powerful earthquake struck southern Japan early Saturday, barely 24 hours after a smaller quake hit the same region. (Kyodo News via AP)

Parents cry as they confirm that their daughter was found dead after an earthquake in Mashiki, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. A major quake shook southwestern Japan, barely a day after another quake hit the same region. (Ryota Tajiri/Kyodo News via AP)

Exterior wall of the city hall fall off after the earthquake in Uto, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. A powerful earthquake struck southern Japan early Saturday, barely 24 hours after a smaller quake hit the same region. (Muneyuki Tomari/Kyodo News via AP)

A cyclist looks at a shopping arcade destroyed by the earthquake in Kumamoto city, southern Japan Saturday, April 16, 2016. A powerful earthquake struck southern Japan early Saturday, barely 24 hours after a smaller quake hit the same region. (Kyodo News via AP)

Residents look for an access to their home on the road which is blocked by a collapsed house, in Mashiki, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. A major quake shook southwestern Japan, barely a day after another quake hit the same region. (Naoya Osato/Kyodo News via AP)

In this aerial photo, the landslide caused by the earthquake disrupts the road in Minamiaso town, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. A powerful earthquake struck southern Japan early Saturday, barely 24 hours after a smaller quake hit the same region.(Kyodo News via AP)

In this aerial photo, the landslide caused by the earthquake disrupts the road in Minamiaso town, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. A powerful earthquake struck southern Japan early Saturday, barely 24 hours after a smaller quake hit the same region.(Muneyuki Tomari/Kyodo News via AP)

Houses are seen in a landslide-hit area in Minamiaso, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. A powerful earthquake struck southern Japan early Saturday, barely 24 hours after a smaller quake hit the same region. (Kyodo News via AP)

A road is split in earthquake-hit in Mashiki, Kumamoto prefecture, southern Japan Saturday, April 16, 2016. A powerful earthquake struck southern Japan early Saturday, barely 24 hours after a smaller quake hit the same region. (Naoya Osato/Kyodo News via AP)

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