The focus of the quake, which hit Niigata at 3:43 am (1943 GMT), was located just five kilometers (three miles) underground, an agency official said, adding the quake initially registered 5.1 on the Richter scale.

There was no danger of tsunami tidal waves, the agency said.

A police spokesman in Niigata, 200 kilometres (125 miles) northwest of Tokyo, said there were no reports of any casualties or damage.

On Monday, a total of 19 tremors, with the strongest measuring 5.9 on the Richter scale and felt in Tokyo, struck the region, slightly injuring 13 people.

On October 23, a powerful earthquake registering 6.8, Japan's deadliest tremor in nine years, hit Niigata, killing 39 people and injuring 2,600 people.

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