A strong earthquake hit Japan's northern coast Saturday near the Fukushima nuclear power plant crippled in the 2011 tsunami.

Japan's Meteorological Agency said the magnitude-6.8 quake struck 6 miles below the sea surface just off the coast of Fukushima. The 4:22 a.m. local time quake rattled buildings in Tokyo, about 120 miles southwest of the epicenter.

A small tsunami reached the coast of Ishinomaki Ayukawa and Ofunato about 50 minutes after the quake. Smaller waves were observed at several other locations along the coast, but changes to the shoreline were not visible on television footage aired by public broadcaster NHK.

Eight towns devastated by the March 2011 earthquake and tsunami, including Rikuzentakata, Higashi Matsushima and Otsuchi, issued evacuation advisories to thousands of households along the northern coast, along with schools and community centers.

All tsunami and evacuation advisories were lifted about two hours after the quake.

Fukushima Dai-ichi – the nuclear plant decimated in the 2011 disaster – and two other nuclear power plants, along with other nuclear facilities along the coast, claimed their reactors and fuel storage pools were being cooled safely, according to Japan's Nuclear Regulation Authority.

Plant operators Tokyo Electric said there were no immediate reports of abnormality after the quake, according to Kyodo news agency.

The meteorological agency advised people to leave the coast immediately, while Japan's public broadcaster NHK said some local authorities issued evacuation advisories to their residents.

The 2011 disaster killed about 19,000 people and triggered multiple catastrophic meltdowns at the Fukushima nuclear facilitiy. More than 100,000 people have been displaced by radiation contamination in communities near the nuclear plant.