A preliminary magnitude 5.9 earthquake struck eastern Japan early Sunday, injuring more than 20 people and disrupting train services in Tokyo and neighboring prefectures, authorities said.

The earthquake struck at about 2 a.m. local time, with its epicenter in southern Ibaraki Prefecture at a depth of approximately 68 kilometers, according to the Japan Meteorological Agency. No tsunami warning was issued.

The quake registered lower 5 on Japan’s seismic intensity scale of 7 in parts of Ibaraki, Saitama and Chiba prefectures, as well as Tokyo’s Adachi Ward. At that intensity, shaking can frighten residents, make it difficult to move without holding onto something and cause objects to fall from shelves.

More than 20 people were reported injured across the region. Among them were a young man and a woman in her 70s in Saitama, nine people in Kanagawa and four in Chiba, according to local fire departments.

Transportation was also affected, with several train operators delaying the start of services or reducing speeds as safety inspections were carried out.

Services on the Keisei Line connecting central Tokyo’s Ueno district with Narita International Airport returned to normal after 9:40 a.m., while some express services operated by Tobu Railway remained suspended.

In Tokyo’s Koto Ward, a water pipe ruptured following the earthquake. Metropolitan authorities were investigating whether the damage was directly caused by the tremor.

Officials reported no abnormalities at the Tokai No. 2 nuclear power plant in Ibaraki or at the Fukushima Daiichi and nearby Fukushima Daini nuclear facilities.

Prime Minister Sanae Takaichi said she had instructed government officials to assess the extent of the damage and provide timely information to the public.

The Japan Meteorological Agency urged residents to remain vigilant for further strong earthquakes over the next week, particularly during the next two to three days.

The earthquake was felt across a wide area of northeastern and central Japan, and an emergency earthquake alert was issued when the tremor struck.