KURIHARA, Japan (AP) -- Soldiers fought their way through a torrent of mud and rocks at a hot spring Sunday, where several people were believed buried after a magnitude 7.2-earthquake hit the mountains of northern Japan, killing at least seven and injuring more than 200.
Rescuers, often forced to resort to shovels and buckets, raced to dig their way through the mire as helicopters kept watch overhead and troops on the ground used backhoes to unblock roads covered by tons of fallen rock, dirt and trees.
Officials said the bodies of three of seven people believed buried at the hot spring were recovered Sunday, bringing the tally of dead to nine. A dozen or so more people were missing.
The seven at the Komanoyu hot spring were believed buried when the side of a hill came crashing down. The resort is located in a heavily forested mountainous area outside the small city of Kurihara, one of the hardest hit, and more than 100 people remained stranded in the region.
The search for survivors - and efforts to recover the dead - were hampered by a series of powerful aftershocks that have rocked the region: More than 470 were recorded since Saturday morning. A rescue effort near a dam where three construction workers were killed was called off Sunday because of fears the dam may have been cracked by the quake.
"It's so frustrating. We have hardly made any progress because of the sludge," said Masahiro Ishibashi, a soldier searching to find the seven missing people at the hot spring.
A group of rescue workers had to suspend their search for a missing construction worker at one of the landslides, where muddy water started gushing out, raising fears of secondary disaster.
Access was also a major problem, with many roads buckled, at least one bridge collapsed and the danger of more landslides along the routes that appeared clear.
Tohoku University geologist Motoki Kazama said the area was especially vulnerable to landslides because it is of volcanic origin, and contains a large amount of loose ash. Some of the landslides swept off the sides of the hills and spread out for several hundred yards, he said.
"With a quake of this magnitude, it isn't surprising that there was this amount of land movement," he said after finishing an inspection near the hot spring.
Emperor Akihito, in an address at a tree-planting ceremony in nearby Akita prefecture, extended his sympathy to those affected by the quake.
"I hope the missing people are rescued promptly," Akihito said. "I hope peace will return to people's lives as soon as possible."
The devastation caused by the quake was focused on a few particularly vulnerable sites, and most of the city was virtually untouched, though residents here remained fearful of the aftershocks.
Train service, water and electricity were restored to most areas. About 2,800 homes in Kurihara city were still without power, however.
"It was so sudden," Yotsuko Haga, whose farmhouse was tilted and declared uninhabitable, said of Saturday's quake. "I just tried to escape to the outside, but I could barely stand."
As she spoke, another aftershock hit, prompting her and her family, who were trying to clean up the home, to run outdoors.
The 8:43 a.m. quake was centered in the northern prefecture (state) of Iwate, and was located about 5 miles underground. It was felt as far away as Tokyo, 250 miles to the southwest.
Japan is one of the most earthquake-prone areas in the world. The most recent major quake in Japan killed more than 6,400 people in the city of Kobe in January 1995.
Along with hundreds of local police and firefighters, the Defense Ministry dispatched a dozen helicopters and patrol aircraft to the region to conduct flyovers and assess the extent of damage.
The government also sent a CH-47 helicopter carrying Disaster Minister Shinya Izumi to the region.