A series of moderate undersea earthquakes shook the Tokyo region early Thursday, including one with a preliminary magnitude of 5.3, the Meteorological Agency said.

One person was slightly injured, but there was no danger of a tsunami from the quakes, officials said.

The magnitude 5.3 quake struck just off the eastern coast of neighboring Chiba prefecture (state) at around 4:15 a.m. local time, according to the agency. It swayed buildings in the capital for about 20 seconds.

In Chiba City, a 29-year-old man suffered a minor injury when a ceiling lamp fell on his face, according to prefectural official Toru Nagaosa.

Several milder temblors followed within hours in the same area.

"I don't think we are in an alarming situation, but we'll stay cautious for a while," Nagaosa said.

A magnitude 5 earthquake rattled the region at 8:20 a.m.

There were no immediate reports of injuries or damage from the quakes.

Japan, which sits atop four tectonic plates, is one of the world's most earthquake-prone countries. Last month, a magnitude 6.8-quake struck northern Japan, killing 11 and causing a fire and small radiation leak at a nuclear power plant.