Tokyo: A moderate earthquake with a preliminary magnitude of 5.9 rattled eastern Japan, including the Tokyo metropolitan area, early Sunday, injuring more than 20 people, most of them slightly, officials said. There was no danger of a tsunami.

According to the Japan Meteorological Agency, the quake occurred in southern Ibaraki prefecture at a depth of 70 kilometres, an area prone to frequent seismic activity. The US Geological Survey recorded a preliminary magnitude of 5.8.

Twenty-three people were injured across four prefectures in the region, nine in Saitama, nine in Kanagawa, four in Chiba, and one in Ibaraki, according to prefectural officials.

Most sustained injuries after falling or hitting themselves against furniture or doors after being caught off guard by the quake while sleeping and getting out of bed in a panic, officials said. Among them was a woman in her 80s who fell from her bed and suffered a serious hip injury in Yokohama, Kanagawa prefecture, the Yomiuri newspaper reported.

The quake caused delays to express trains serving Tokyo and Narita Airport alongside other local services operating in north-eastern regions, though Shinkansen bullet trains operated normally, according to East Japan Railway Company.

The government established a task force to evaluate the extent of potential damage, Prime Minister Sanae Takaichi stated on social media platform X.

The temblor triggered emergency earthquake alerts on mobile phones and caused significant shaking in Tokyo. NHK public television broadcast footage showing traffic on roads in nearby cities, including Mito and Saitama, moving normally.

An underground water pipe burst in Tokyo's eastern ward of Koto, sending water pouring onto the road, NHK footage showed. The pipe was subsequently repaired, and the leak stopped. The earthquake also caused power outages affecting roughly 460 households in Tokyo, but service was restored later on Sunday morning, according to TEPCO Power Grid.

There were no reports of irregularities from the roughly dozen nuclear power plants and related nuclear material facilities in the region, the Nuclear Regulation Authority confirmed.

Last month, a magnitude 7.1 earthquake struck the Kumamoto region on Japan's southernmost main island of Kyushu, killing 38 people, injuring 364, destroying over 1,500 buildings, and damaging nearly 20,000 others.

AP