5.1 magnitude earthquake strikes Kumamoto prefecture, Japan
The earthquake measured 4.9 magnitude according to the Japanese meteorological agency.
Its depth was 10km (6.2 miles), according to the USGS.
The epicenter of the quake was located 17.9km (11.1 miles) southwest of the city of Kumamoto, inhabited by over 680,000 people.
The high-speed rail service has been suspended, according to JR railway operator, although train services will resume shortly, it added.
Nuclear power plants at Sendai and Genkai are safe, according to Kyushu Electric Power, as cited by TASS.
A devastating magnitude 7.1 earthquake struck Kumamoto earlier in April, killing at least 11 people and injuring many others. Its epicenter was located just 1km southwest of the city, according to the USGS.
The powerful quake, followed by an aftershock and a tsunami advisory, caused buildings to collapse and brought down power lines.
The April earthquake is the deadliest since 2011 magnitude 9.0 undersea quake which struck off the coast of Japan, killing some 16,000 people and causing enormous damage to the country.