Tokyo: At least 21 people have been killed and over 1,800 injured in a series of powerful earthquakes and aftershocks that rocked parts of Japan, prompting Government to press into action military helicopters for evacuating thousands of people from their flattened houses.

A tremor measuring 6.8 on Richter scale centred in Ojiya, about 260 km northwest of Tokyo rocked the area last evening (Oct 23, 2004), knocking a bullet train from its rails, overturning cars and rattling buildings as far away as the Japanese capital, State media reported today (Oct 24, 2004).

Several strong quakes followed through the night, and aftershocks continued to jolt the area this morning, Kyodo news agency reported.

At least 19 people, most of them elderly or children were killed, over 1,500 were injured and at least seven were reported missing in Niigata prefecture yesterday, it said.

Amidst fear of more powerful aftershocks, the Defence agency dispatched 230 personnel in vehicles and helicopters to rescue stranded residents and provide clean water. Around 68,000 people were evacuated from Niigata alone.

The earthquakes were the deadliest to hit tremor-prone Japan since 1995 when 6,433 people were killed and 43,700 injured when the western city of Kobe was devastated by a quake measuring 7.3 on the Richter scale.

Meanwhile, Prime Minister Junichiro Koizumi said the Government will compile a supplementary budget for reconstruction work. The Government also established an emergency headquarters to deal with the Niigata-Ken Chuetsu earthquake.