TOKYO, July 23: A strong earthquake measuring 6.8 on the Richter scale shook northern Japan early on Thursday, injuring more than a dozen people as the force shattered windows and set off fires, officials said.

The earthquake struck as most people were asleep in the north of the main Japanese island of Honshu, near where a deadly tremor hit just a month ago.

“I’ve never felt such a big tremor in my life,” said Hirokatsu Hashimoto, an official in the northern city of Hachinohe.

At least 13 people in the city were taken to hospital after the earthquake, said Katsuyasu Sasaki, an official of Hachinohe City Hospital. He said doctors were assessing how seriously they were hurt.

Fire engines and five ambulances rushed through the city with sirens blaring after authorities heard that fire had broken out due to the earthquake.

The tremor struck at 0:26 am (1526 GMT Wednesday) in Iwate prefecture, the Japan Meteorological Agency said. It was centred 120 kilometres underground.

“I woke up with a big shock. I was wondering what the hell was going on,” said Takashi Kato, an official of Morioka, a city close to the epicentre.

“I haven’t received any immediate report of damage, but part of the city hall ceiling was damaged,” Kato said. In Tokyo, Prime Minister Yasuo Fukuda said he had ordered officials to “do their best” to rescue any people trapped by the earthquake.

“It was shaking a little at first and then suddenly we felt a big rolling feeling,” said Ryuichi Takedaka, an official at the Hirono town office near the epicentre.

“It continued rolling for a while,” he told public broadcaster NHK. “I walked to the office and saw glass windows shattered at some houses along the way.” Television footage showed office floors covered in paper that had been shaken from the desks.

“It was a strong quake but I didn’t see things fall from the shelves,” said Yasuko Tomabechi, a rice farmer in the northern city of Towada.—AFP