(Newser) – A strong earthquake rattled Japan in the wee hours and raised alerts at the crippled Fukushima nuclear plant, but so far, all looks fine. The earthquake of magnitude 7.3 struck off Japan's east coast at 2:10am Saturday local time, the US Geological Survey said. Japan's emergency agencies declared a tsunami warning for the region that includes the Fukushima site. Japanese broadcaster NHK reported that plant operator TEPCO ordered workers near the coast to move to higher ground. No damage has been reported on land, though the tremor was felt in Tokyo, some 300 miles away. (Read more Japan stories.)