The official death toll from Friday's earthquake and tsunami has exceeded 687, but as many as 10,000 were unaccounted for in one coastal town, MSNBC said Saturday.
"This is the largest earthquake since the Meiji Era, and it is believed that more than 1,000 people have lost their lives," said Japanese Chief Cabinet Secretary Yukio Edano.
Officials said at least 3,400 buildings were partially or completely destroyed, and in Iwate prefecture the coastal city of Rikuzentakata was virtually destroyed by a tidal wave following the 8.9-magnitude earthquake that hit shortly after 2 p.m. Friday, Kyodo News reported.
The entire city was under water and just a few buildings remained in the urban area, officials said. Officials said the tsunami reached as high as the third floor of City Hall.
Officials in Miyagi prefecture said Saturday there has been no communication with about 10,000 people in Minamisanriku -- more than half the town's total population, Kyodo said.
Millions were without power and water and an explosion at the Fukushima nuclear plant has forced the evacuation of more than 210,000 people.
Fires continued to burn in residential areas, with Kesennuma in Miyagi prefecture experiencing three major blazes. The coastal area of Miyako City and most of the town of Yamada were under water.
"More than 90 percent of the houses in three coastal communities have been washed away by tsunami," said an official in the town of Futaba in Fukushima prefecture. "Looking from the fourth floor of the town hall, I see no houses standing."
A magnitude-6.7 earthquake Saturday rocked an inland area on the Sea of Japan coast northwest of Tokyo, hitting Nagano and Niigata prefectures.
Japan's Nuclear and Industrial Safety Agency said radioactive cesium and iodine were detected around Japan's No. 1 nuclear reactor.