6.57 pm: No problems detected in N-plants after earthquake
The UN atomic agency said it had been informed by Japanese authorities that no problems had been detected at nuclear power plants in the region nearest to the epicentre of Friday's earthquake.
The International Atomic Energy Agency said its Incident and Emergency Centre had been in contact with Japan's Nuclear Regulation Authority (NRA) "to collect information about the status of... nuclear power plants that could be affected".
"Nuclear power plants in the region nearest to the epicentre of the earthquake have reported to NRA that they have detected no trouble, and that no emergency measures have been activated," Gill Tudor, a spokeswoman for the Vienna-based UN agency, said in a statement.
4.00 pm: All Tsunami warnings lifted
All Tsunami warnings for the northeast coast of Japan have been lifted by the Japan Meteorological Agency.
Japan's meteorological agency says that the magnitude 7.3 quake is aftershock from last year's magnitude 9, reported Kyodo News.
3. 50 pm: 9 people injured in quake
Rowan Hooper, News Editor with New Scientist just reported that 9 people have been injured in the Japan quake.
3. 40 pm: According to the United States Geological Survey, there are no immediate reports of any fatalities after the 7.3-magnitude quake that was followed by a 6.2 aftershock.
Here are some reactions on Twitter after the earthquake hit Japan:
3. 30 pm: Some residents blame the authorities for not issuing a warning ahead of the earthquake, although the meteorological department was aware of it.
3. 10 pm: Residents near Miyagi prefecture asked to evacuate
Residents of at least one town, Minamisanriku in Miyagi prefecture, were advised to get to safety, with reports suggesting other towns were also affected.
“We are now calling on people to evacuate to higher ground,” town official Ryuichi Omori told AFP.
“It’s already pitch dark here. Calls phones – both landlines and mobiles – are not going through now, which makes it difficult to see people’s movement.
A presenter on state broadcaster NHK repeatedly told viewers to get to safety after the initial tremors, which set Tokyo buildings swaying violently.
Alex Ogle, a journalist with the AFP tweeted out a video of the Japan earthquake shaking the Kyodo newsroom.
2.50 pm: Tsunami hits Japan's Miyagi prefecture
Following a 7.3-magnitude quake, a meter-high tsunami struck Japan’s Miyagi prefecture, the location of the ravaged Fukushima nuclear plant. Authorities reported no damage, and said that radiation levels at Fukushima remain stable.
The earthquake struck on Friday off the coast of northeastern Japan in the same region that was hit by a massive earthquake and tsunami in March 2011. Authorities issued a warning of a possible tsunami.
The Japan Meteorological Agency said the earthquake had a preliminary magnitude of 7.3 and struck in the Pacific Ocean off the coast of Miyagi prefecture at 5:18 p.m. (0818 GMT). The epicenter was 10 kilometers (6.2 miles) beneath the seabed.
The warning said the tsunami could be as high as 2 meters (2.19 yards).
NHK television broke off regular programming to warn that a strong quake was due to hit shortly before the earthquake struck. Afterward, the announcer repeatedly urged all near the coast to flee to higher ground.
Buildings in Tokyo swayed for at least several minutes.
The magnitude-9.0 earthquake and ensuing tsunami that slammed into northeastern Japan on 11 March, 2011, killed or left missing some 19,000 people, devastating much of the coast. All but two of Japan's nuclear plants were shut down for checks after the earthquake and tsunami caused meltdowns at the Fukushima Dai-Ichi nuclear plant in the worst nuclear disaster since the 1986 Chernobyl disaster.
Immediately following Friday's quake, there were no problems at any of the nuclear plants operated by Fukushima Dai-Ichi operator Tokyo Electric Power Co., said a TEPCO spokesman, Takeo Iwamoto.
With inputs from Agencies