About 2000 bodies have been found on two shores of Japan's Miyagi prefecture, where a 10-metre tsunami followed a magnitude 9 quake on Friday, the Kyodo news agency reports.
Half were found on the Ojika peninsula and another 1000 in the town of Minamisanriku, which was flattened by the tsunami.
The prefecture was the region worst-hit by the tsunami
Police have warned the number of dead in Miyagi could exceed 10,000.
Tensions increased in the region on Monday as soldiers and officials along a stretch of the northeastern coast warned residents it could be hit by another tsunami, and ordered them to higher ground.
The crew of a helicopter flying out at sea reported a 3 metre-high wave.
The tsunami did not form, even though in Sendai, the biggest city in the area, police announced warnings on a public address system.
Japanese Prime Minister Naoto Kan says his country is facing its greatest hardships since World War II.
In a televised statement, Mr Kan called on people to pull together, saying Japan could overcome the crisis.
Millions of people are without power or water and thousands have spent another freezing night huddled in shelters, three days after the quake and tsunami.
The northeastern coast, including the city of Sendai, is a scene of devastation, and strong aftershocks are continuing.
Almost 2 million households are without power in the north, the government says, with about 1.4 million without running water. Kyodo news agency says about 300,000 people were evacuated nationwide.
The Prime Minister says food, water and other necessities such as blankets are being delivered by vehicles but because of damage to roads, authorities are considering air and sea transport. Huge contingents of troops and police are being sent to help with rescue efforts.
Mr Kan says the government is preparing to double the number of troops mobilised to 100,000.
He also approved a power outage plan by the Toyko Electric Power Co beginning on Monday to address the power shortage partly caused by the shutdown of several nuclear power stations.
The rolling blackout is likely to affect 3 million customers, including large factories, buildings and households, the company says.
