A strong earthquake with a preliminary magnitude of 7.4 has jolted Japan's Miyagi prefecture, which was devastated by last month's deadly quake and tsunami.
The quake, which hit at 11:32pm (local time), struck 66 kilometres east of Sendai, according to the US Geological Centre.
The quake, which the USGS says hit 25.6 kilometres under the water, shook buildings as far away as Tokyo.
The quake that preceded last month's tsunami was magnitude 9.0.
Japan's weather bureau issued a tsunami alert for the Pacific coast, saying that waves of up to two metres could hit the shoreline.
Fresh alert: Japan's public television urged those in areas where the tsunami warnings were issued to evacuate to higher ground
In a statement on its website, the Hawaii-based Pacific Tsunami Warning Center said it did not expect a Pacific-wide tsunami.
Japan's NHK public television urged those in areas where the tsunami warnings were issued to evacuate to higher ground.
Workers battling to control the stricken Fukushima nuclear plant were also ordered to evacuate the area, operator TEPCO said.
Officials say the earthquake causd no further damage to the crippled plant.
Workers have been grappling to secure damaged reactors at the plant, which was badly hit by the massive tsunami that hit Japan's north-east on March 11.
Cooling systems were knocked out, leaving the temperature of the nuclear cores to rise and setting off a scramble to prevent a meltdown.
Thursday's quake comes as the number of people confirmed dead after last month's earthquake and tsunami rose to 12,608, with a further 15,073 listed as missing.
The updated toll revised the number of dead and missing people to 27,681, after it briefly topped 28,000 last week, the National Police Agency said on Thursday.
The quake has become Japan's deadliest natural disaster since the 1923 Great Kanto Earthquake, which killed more than 142,000 people.
Nearly 160,000 people are still sheltered in emergency facilities nearly four weeks after the double disaster.
Source: ABC News