An earthquake with a preliminary magnitude of 5.5 rocked a wide area in northeastern Japan early Tuesday, the weather agency said, adding there was no threat of a tsunami.

The quake occurred at 4:33 a.m., registering 4 on the Japanese seismic intensity scale of 7 in parts of Iwate, Miyagi and Fukushima prefectures, according to the Japan Meteorological Agency.

The temblor, which occurred at a depth of 60 kilometers in waters off Miyagi Prefecture, measured 4 in areas including Iwate's Ichinoseki, Miyagi's Ishinomaki and Fukushima's Tamura, it said.

No abnormalities have been reported at the Onagawa nuclear plant, near Ishinomaki, the operator said.

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