TOKYO - Strong quakes jolted Kyushu area in southwestern Japan at around 9:26 pm and 10:07 pm local time Thursday, with local reports saying several people in the region were injured.

The first quake measured at 6.4 magnitude was registered at level 7 at Japan's seismic intensity of 7 in parts of Kumamoto Prefecture and the second 5.7-magnitude quake logged at lower 6. both quakes triggered no tsunami warnings, according to the Japan Meteorological Agency.

Local reports said that strong tremor lasted about 30 seconds during the first attack and Shinkansen bullet train services were suspended by the strong quake.

The epicenter was detected at 32.7 degree north latitude and 130.8 degree longitude with a depth of 10 km.

Some concrete pieces fell down from buildings and many people came out from buildings standing on the street in Kumamoto city, according to Japan's broadcaster NHK TV footage.

NHK said that polices in Kumamoto Prefecture received reports of injuries and several buildings may have collapsed in the area near the epicenter.

No abnormalities were found in the Sendai nuclear power plant, the only operating nuclear facility in the area.

The Japanese government has set up a special group to gather information on injuries and damage, said top government spokesman Yoshihide Suga.