Tokyo, Japan: Authorities said a 6.8-magnitude earthquake struck Japan's northeastern coast on Saturday (May 1st), but no tsunami warning was given and no damage was reported immediately.

The mid-morning quake struck at a depth of 47 kilometres in the Pacific, near the epicenter of a massive 2011 quake that caused a massive tsunami that killed more than 18,000 people, according to the United States Geological Survey (USGS).

Following Saturday's jolt, which shook parts of the eastern coast while tremors were felt in Tokyo, Japan's meteorological agency said there was no tsunami danger.

"We are still collecting information but have not received any reports of injuries or damage," Tomoki Sawata, a spokesman for the local government, told AFP that the quake was "fairly strong".

Local railway companies have halted operations, including shinkansen bullet trains, according to public broadcaster NHK, while elevators in some Miyagi buildings have stopped working.

TEPCO, the operator of the Fukushima nuclear power plant, said the site, which melted down in the aftermath of the 2011 tsunami, showed no anomalies after the latest jolt.

"Operations are underway as usual," TEPCO spokesman Koichiro Shiraki said.

Japan is located on the Pacific "Ring of Fire," an area of active seismicity that extends from Southeast Asia to the Pacific basin.

The country is prone to earthquakes, and there are stringent building codes in place to ensure that structures can withstand severe tremors.

A powerful 7.2-magnitude earthquake struck off the northeastern coast in March. The Japanese government issued a tsunami warning, but the coastline was unaffected.

Another powerful quake struck the area in February, injuring dozens of people. It was an aftershock of the 2011 earthquake, according to meteorologists.