A magnitude 6.4 earthquake registering a lower 5 on the Japanese intensity scale struck off Fukushima and Miyagi prefectures on Sunday evening, the Meteorological Agency has said.

The epicenter of the quake, which occurred at around 7:23 p.m. at a depth of about 45 kilometers (28 miles), was offshore, the agency said.

No tsunami warning was issued.

There were no immediate reports of major damage or of any casualties, according to authorities.

Fukushima Prefecture is home to the crippled Fukushima No. 1 nuclear power plant.

No abnormalities were found at nuclear power stations in the region, including both the Fukushima No. 1 and No. 2 plants, according to their operators.

The quake registered lower 5 on the Japanese seismic intensity scale of 7 in Futaba in Fukushima and at Ishinomaki and Watari, which are both in Miyagi, according to the weather agency.

The strong quake was also felt in Tokyo, about 250 km away, where it shook buildings and measured 3 on the intensity scale.

“Judging from the location where it occurred, the temblor was likely an aftershock of the March 2011 earthquake,” said Masaki Nakamura, director of the agency’s Earthquake and Tsunami Observation Division, at a news conference Sunday.

He called on residents in affected areas to remain alert for quakes of up to lower 5 on the Japanese scale for the next week or so.

The 2011 quake, with a magnitude of 9.0, and subsequent huge tsunami severely damaged Miyagi, Fukushima and Iwate prefectures, leaving a total of more than 18,000 people in the three prefectures and other areas dead or missing, and causing an unprecedented triple meltdown at the Fukushima No. 1 nuclear plant.