TOKYO - A powerful 6.9-magnitude earthquake hit northeast Japan on Tuesday, sparking panic and triggering a tsunami including a one-metre (three-foot) wave that crashed ashore at the stricken Fukushima nuclear power plant. National broadcaster NHK urged residents to “flee immediately” to higher ground, reminding viewers to heed the lessons of the “Great East Japan Earthquake”. A massive undersea quake with a magnitude of 9.0 that struck in March 2011 unleashed a tsunami that left more than 18,500 people dead or missing. It sent three reactors into meltdown at the Fukushima Daiichi power plant in one of the world’s worst nuclear disasters. An official from plant operator TEPCO told a news conference that a one-metre wave had hit the coast at the facility, but a company spokesman told AFP there were no reports of damage. About a dozen other waves were recorded elsewhere on the northeast coast, according to the Meterological Agency, but they were smaller than initial warnings of waves as high as 3.0 metres.

The biggest, measuring 1.4 metres, hit the port at Sendai north of Fukushima, but officials said there were no reports of damage there. NHK aired rolling coverage of the earthquake, with the words “Tsunami! Flee!” in white lettering over a bright red band on the screen. The Meterological Agency lifted its final tsunami warning nearly seven hours after the earthquake struck.

TEPCO earlier reported that a water cooling system at a reactor in the separate Fukushima Daini facility had briefly stopped, in an automatic response, but that it was back up and operating. “The biggest risk now is a case whereby contaminated water is carried away with the tsunami, which pollutes the environment,” TEPCO’s chief decommissioning officer Naohiro Masuda told reporters, of the situation at Fukushima Daiichi.