An earthquake with a preliminary magnitude of 5.5 struck the Kanto region in eastern Japan on Monday afternoon, but there were no immediate reports of damage and injuries and no tsunami warning, Kyodo news agency reported.

The quake was centered north of Saitama Prefecture at a depth of about 56 kilometers. It shook areas in the vicinity including Tokyo, Ibaraki, Chiba and Kanagawa prefectures, temporarily disrupting air and train services.

No irregularities were found at nuclear power plants in Ibaraki and Fukushima prefectures, the Nuclear Regulation Authority said.