TOKYO (Reuters) - A strong earthquake hit southwestern Japan on Thursday, bringing down some buildings, killing at least nine people and injuring hundreds, local media said, but the nuclear regulator reported no problems at power plants.

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The initial magnitude 6 tremor struck 11 km (7 miles) east of the city of Kumamoto, according to the U.S. Geological Survey (USGS). It said the magnitude was 6.2 but later revised it down.

There was no tsunami warning, but at least one person was killed after being crushed by a collapsing building, local media reported. More than 400 people were taken to hospital.

The Kyodo news agency said some 44,400 people had also been evacuated and more than 100 aftershocks had been recorded since the quake, which struck shortly before 9.30 pm local time.

Footage from public broadcaster NHK showed firefighters tackling a blaze in a building in Mashiki, a town of about 34,000 people near the epicenter of the quake.

“We will do our utmost and carry on with life-saving and rescue operations throughout the night,” Prime Minister Shinzo Abe told reporters.

Japanese media showed residents, some of them wrapped in blankets, huddling in parking lots and other open space for fear of further building collapses.

“The apartment building I live in is now tilting. Everything fell down inside. It’s a mess,” a male resident in Mashiki said on NHK.

About 16,500 households in and around Mashiki were without electricity as of 2 a.m. (1700 GMT), according to Kyushu Electric Power Co Inc 9508.T.

The Nuclear Regulation Authority said there were no irregularities at three nuclear plants on the southern major island of Kyushu and nearby Shikoku.

In March 2011, a quake of magnitude 9 struck offshore north of Tokyo, causing tsunami waves along the coast that killed nearly 20,000 people and triggered a nuclear power plant meltdown.

After Thursday’s quake, some high-speed trains were halted as a precaution.

Bank of Japan Governor Haruhiko Kuroda, speaking in Washington, said the central bank as working closely with other authorities to avoid any disruption to banking operations. There has been no report of disruption to fund settlement systems so far, he said.

Honda Motor Co 7267.T suspended output at its motorcycle factory near Kumamoto following the quake, a company spokesman said. Honda planned to inspect production equipment at the factory, which has an annual output capacity of 250,000 units, on Friday to see how soon production can be resumed.

Mitsubishi Electric Corp 6503.T and tire maker Bridgestone Corp 5108.T also suspended operations at their factories in the area, Kyodo news agency said.