Heavy rains that could trigger landslides are hampering Japan's efforts to recover from one of the most deadly earthquakes to hit the country in a decade.
Prime Minister Junichiro Koizumi today flew to the devastated area in an attempt to lift the spirits of the thousands left homeless, and to see the damage caused by Saturday's quake and aftershocks that killed 27 people.
Many of the 100,000 survivors of the weekend earthquakes have not been reached by rescue services.
More than 2,900 people were injured and three, including two children, are still missing after the quakes that rocked rural Niigata prefecture, 150 miles north of Tokyo.
About 47,000 people have been evacuated from their homes in Nagaoka, Niigata's second biggest city with a population of around 200,000.
Several small communities in the mountainous, rice-growing region are still cut off, local media say, and soldiers are continuing efforts to get aid to them.
While the number of aftershocks have tapered off, worried authorities are warning that thousands of quake-weakened buildings still pose a threat to life.
The tremors follow a record 10 typhoons to hit Japan this year, including one that killed at least 80 people last week. Saturday's initial earthquake, with a magnitude of 6.8, was the deadliest in Japan since the Kobe earthquake killed more than 6,400 people in 1995.