Experts have warned that powerful aftershocks were likely to strike the Japanese island of Hokkaido in coming days after a strong earthquake battered the area injuring nearly 600 people.
A government team visited the earthquake-prone region to assess damage from powerful earthquakes that struck at dawn yesterday with an initial tremor of 8.0 on the Richter scale - stronger than some fatal quakes that have hit the country.
Aftershocks powerful enough to cause heavy damage in the northern region were highly possible, seismologists said.
"Although the number of tremors has been declining, there is a high possibility of strong aftershocks striking the region," said an official at Japan's Meteorological Agency.
"There is a 70 per cent chance that aftershocks with magnitude of six or higher could hit the region in the next three days," he said.
There was a 20 per cent possibility of aftershocks with magnitude of seven or stronger in the next three days, he said.
Yesterday's earthquake had injured at least 572 people, destroyed or caused heavy damage to 77 homes and forced about 13,000 people to flee from their homes, police said.