An earthquake with a preliminary magnitude of 5.2 jolted eastern Japan early Thursday, including Chiba Prefecture and downtown Tokyo, leaving several people injured, according to the Japanese weather agency and local authorities.

The 4:16 a.m. quake registered upper 5 on the Japanese earthquake intensity scale of 7 in Kisarazu and lower 5 in Kimitsu, both in Chiba Prefecture, and 4 in areas including Tokyo's Chiyoda and Shinagawa wards, according to the Meteorological Agency. No tsunami warning was issued.

The agency defines an upper 5 on the shindo scale as a situation in which many people find it difficult to walk. It was the first time since March 2012 that Chiba Prefecture had been rocked by an upper 5 quake, according to the agency.