It was the first time in Japan that three earthquakes with an intensity of lower 6 or above on the Japanese seismic intensity scale have been recorded the same day, according to the agency.

The strongest of the quakes jolted the towns of Nango, Yamoto and Naruse in Miyagi Prefecture at 7:13 a.m. with an estimated magnitude of 6.2 on the Richter scale and an intensity of upper 6 on the Japanese scale of 7.

This was followed by an aftershock at around 4:56 p.m. that measured 5.3 on the Richter scale and lower 6 on the Japanese scale in the town of Kanan, northern Miyagi.

The series of quakes in the region began with one at 12:13 a.m. the same day measuring 5.5 on the Richter scale and a lower 6 on the Japanese scale in Kanan, Wakuya, Monou and Kogata in Miyagi.

A quake of upper 6 on the Japanese scale is strong enough to cause most unreinforced concrete walls to collapse. In one of lower 6 intensity, people will find it difficult to remain standing.

According to the Miyagi prefectural police, 421 people were hurt in the quakes, of whom 27 were seriously injured. There have been no reports of dead or missing people.

The prefectural government said 480 residences and public facilities were damaged.

The Disaster Relief Law is applicable to the towns of Nango, Yamoto, Naruse, Kanan and Kashimadai, it said.

Up to 8 p.m. there had been about 220 aftershocks strong enough to be felt. The agency has urged caution in light of continuing aftershocks as well as heavy-rain alerts in effect for Miyagi and Iwate prefectures. More than 2,000 residents were evacuated to elementary schools and other facilities in 12 municipalities as evacuation orders were issued for some areas.

The government has set up an office at the crisis management center at the Prime Minister's Office.

Yoshitada Konoike, state minister for disaster prevention, held a news conference in the afternoon and said he will lead a government inspection team to the affected areas on Sunday.

Responding to the prefecture's request for help in the worst-affected areas of Naruse, Yamoto and Nango, about 300 Ground Self-Defense Force personnel were dispatched to begin clearing collapsed homes and other facilities.

According to the Miyagi prefectural police, two people were rescued after being buried in a mudslide in Kanan town that affected three households.

Tohoku Electric Power Co. said about 100,000 households in the prefecture were temporarily without power. In Sendai and other places, over 13,000 were without running water.

Miyagi prefectural government officials said a four-car train on the JR Ishinomaki Line in Kanan derailed due to the second quake, but there were no reports of injuries among the 10 passengers onboard.

JR East said a total of 262 Shinkansen bullet trains and local trains in the region were canceled, affecting some 120,000 passengers.

Traffic was also halted temporarily on highways such as the Tohoku Expressway.

Meanwhile, Tokyo Electric Power Co. and Tohoku Electric Power said nothing unusual was observed at the Fukushima No. 1 and No. 2 nuclear power plants in neighboring Fukushima Prefecture and the Onagawa nuclear power station in Miyagi.

Tohoku Electric said it will delay the resumption of operations of a reactor at the Onagawa plant, scheduled for Saturday night, in light of the quakes. The reactor had been shut down due to abnormalities.

The two nuclear power plants in Fukushima were already shut down for regular inspections.

The meteorological agency said the epicenters of the three quakes were all about 12 kilometers underground in northern Miyagi.

The agency said it was the first time since 1949 that a series of earthquakes of around magnitude 6 had occurred consecutively.

(EDS: UPDATING FIGURE IN 10TH PARA)