More indications are emerging of the scale of the destruction caused by Friday's earthquake in Japan and the tsunami waves that were triggered.
Police have warned that the death toll in tsunami-hit Miyagi prefecture alone could exceed 10,000, national public broadcaster NHK reports.
On Sunday, the National Police Agency said in a statement the confirmed death toll from Friday's twin disasters was 688, with 642 missing and 1570 injured.
However, in the small port town of Minamisanriku in Miyagi prefecture about 10,000 people are unaccounted for. NHK says that amounts to more than half the population of the town.
In Mito, another town in the area, long lines formed outside a damaged supermarket as hundreds waited for medicine, water and other supplies.
The Japan Rail service is in chaos, some of its carriages buried in mud or laying twisted on farmland. Four trains in Miyagi and Iwate prefectures are missing.
Officials announced on Sunday that the number of military personnel involved in the search and rescue operation would be doubled to 100,000.
Police say more than 200 bodies were found in the city of Higashimatsushima on Sunday.
NHK has reported that soldiers have found hundreds of bodies in the town of Rikuzentakada in the Iwate prefecture.
Hundreds of other residents in the city's Nobiru district are unaccounted for, according to media reports.
Police in the city of Sendai said up to 300 bodies had been found on the shoreline.
Amid a mass rescue effort there were grim updates indicating severe loss of life along the hard-hit east coast of Honshu island, where the monster waves destroyed or damaged more than 12,250 homes and other buildings.
Police said more than 215,000 people are huddled in emergency shelters.
At least 2400 houses were flooded by the tsunami, while more than 100 houses had been burned, police said, adding that there were 60 landslides.
The power of the earthquake was such that the main island of Japan shifted 2.4 metres, the US Geological Survey said.
Italy's National Institute of Geophysics and Volcanology said the earth's axis shifted 25cm as a result of the quake.
Japan's worst previous earthquake was of 8.3-magnitude in Kanto in 1923, which killed 143,000 people. A 7.2 quake in Kobe killed 6400 people in 1995.