An 81-year-old man died of a heart attack at a hospital in Ojiya after feeling a powerful aftershock in Niigata prefecture 200 kilometres (125 miles) northwest of Tokyo, a National Police Agency spokesman said.

In nearby Nagaoka, a 73-year-old man died of cerebral hemorrhage and a 59-year-old man succumbed to respiratory problems after they were taken to hospital following tremors, the spokesman said.

A 68-year-old woman died of cerebral hemorrhage at a hospital in the township of Yamato in the Niigata region by the Sea of Japan (East Sea).

Elsewhere a 91-year-old man slipped into a coma and died and another man aged 80 fell victim to a stroke.

The toll from the earthquake has been rising as residents -- particularly the elderly -- are worn down physically and mentally. Hundreds of aftershocks have hit since the first quake late Saturday of 6.8 on the Richter scale.

Police also found under the mud of a landslide a car belonging to a 39-year-old woman who went missing with her three-year-old daughter and two-year-old son. The three were not immediately located.

The public Japan Broadcasting Corp. reported nearly 3,400 people had been treated for injuries, higher than the toll given by police.

Nearly 103,000 people are staying at 486 shelters after leaving their homes for safety.

Roads were damaged at 1,819 points and there were 151 landslides, the National Police Agency said. A total of 395 houses were destroyed and 3,473 houses partly damaged.

The earthquake was the deadliest to hit tremor-prone Japan since 1995, when 6,433 people were killed in the western city of Kobe.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.