One of the most powerful earthquakes to rock the Kansai region in decades struck Osaka and neighboring prefectures Monday morning, leaving at least four people dead and more than 300 injured.

The earthquake, which had a magnitude of 6.1 and registered lower 6 on the Japanese intensity scale to 7, hit at 7:58 a.m. at a depth of about 13 km under northern Osaka, the Meteorological Agency said. No tsunami warning was issued.

The quake literally woke the Kansai region and underscored the fact that the region remains just as vulnerable as other parts of Japan that have been more seismically active since the magnitude 7.3 Great Hanshin Earthquake killed 6,434 people and left Kobe devastated in 1995.

Osaka officials were still assessing the damage as of Monday evening.

Rina Miyake, a 9-year-old girl in Takatsuki, Osaka Prefecture, was confirmed dead after a wall surrounding a swimming pool fell on her as she walked past.

Also in the prefecture, Motochika Goto, a man in his 80s from Ibaraki, died after he was crushed by a bookshelf at his home, according to the Osaka Prefectural Government.

In Higashiyodogawa Ward in the city of Osaka, 80-year-old Minoru Yasui died after being hit by a falling wall.

Later in the day, a fourth death was reported in Takatsuki, Osaka Prefecture, where an 81-year-old woman was confirmed dead after she was crushed under a dislodged chest of drawers in her house, city officials said.

Dozens of fires were reported in Osaka, Hyogo, Kyoto and Mie prefectures, according to police and municipal authorities.

In Takatsuki and Ibaraki, gas supplies to 108,000 locations were interrupted, Osaka Gas Co. said, while a water pipe under a road in Takatsuki burst and flooded the area, according to the police.

Kansai Electric Power Co., meanwhile, said its nuclear plants in Fukui Prefecture were operating normally. No abnormalities were reported at the Takahama, Mihama and Oi plants in the prefecture.

In the city of Osaka, initial fears of widespread panic and chaos had receded by midday after subway services to parts of the city center were gradually restored.

Life on the streets in the Umeda and Namba districts had largely returned to normal, although the major shopping centers around Osaka Station were closed and the crowds were smaller than normal. Some posted notices in both Japanese and English announcing they were closed for the day because of the quake.

By late Monday afternoon, worries about aftershocks were growing. A few convenience stores appeared to be running low on certain items.

“We’ve done a brisk business these past few hours, especially in bottled water,” said Tetsunari Nigawa, who works at a convenience store near central Osaka’s Umeda Station.

At Namba Station, groups of foreign and Japanese tourists found transportation to Kansai International Airport greatly curtailed, with the fastest trains suspended and only one, a non-reserved train, in operation.

Bus services from the airport to parts of Kansai including Wakayama and Nara prefectures had partially resumed by mid-afternoon.

Up to 70 people were seen standing calmly in line at taxi stands in Umeda Station. By Monday night, most of the main north-south Midosuji Subway Line and other city subway lines that run through central Osaka had reopened.

“It was a strong quake and reminded me of the 1995 earthquake. It was quite a surprise,” said Yoko Inoue, 38, who was waiting for a taxi near Umeda Station.

Kepco said late Monday afternoon that there were still some power outages in their service areas.

With rain forecast, the Meteorological Agency warned against landslides, adding that people should be wary that aftershocks might hit in the next few days.

Soon after the morning quake, the government set up an emergency task force in Tokyo to gather information about the situation.

The central government vowed to “do its utmost” with disaster-relief efforts and to help with reconstruction, as well as provide the public with more information.

Learning of Miyake’s death, Chief Cabinet Secretary Yoshihide Suga, speaking in Tokyo, said the government instructed the education ministry to re-evaluate nationwide safety standards for cinder block walls along school commuting routes.

As of Monday afternoon, more than 1,100 residents were taking refuge in 462 evacuation centers in Osaka Prefecture, prefectural officials added.

The top government spokesman also urged residents in the hardest-hit areas to stay calm and be vigilant against aftershocks, which he said could be as strong as a lower 6, over the next week or so.

A senior government official expressed guarded optimism about the damage, citing what appeared to be the quake’s “localized” nature.

More than 60 bullet trains were canceled in the morning and some expressways were closed. Both Kansai International and Kobe airport temporarily closed but resumed operations after confirming there was no structural damage.

In Osaka Prefecture, power was restored after the quake left about 170,800 homes and buildings without electricity for several hours.

The quake left many commuters stranded at stations or on streets during the morning rush hour after disrupting shinkansen and other rail operations in western and central Japan.

In a quake with an intensity of lower 6, it is difficult to remain standing, and unsecured furniture may move or topple over, according to the Meteorological Agency.

Although the magnitude was relatively weak, the quake is believed to have triggered high-intensity tremors because it struck at a shallow depth.

It was the latest in a string of quakes over the past few days, including a magnitude 4.6 quake that hit southern Gunma Prefecture on Sunday and a magnitude 4.5 temblor that struck Chiba Prefecture on Saturday.

Staff writer Tomohiro Osaki contributed to this report. Information from Kyodo added.