An earthquake with preliminary magnitude of 7.3 has struck off the coast of Fukushima prefecture in Japan.
A tsunami warning for waves of up to three meters (10 feet) has been issued.
The Japan Meteorological Agency says the quake struck around 6 a.m at a depth of 10 kilometres (6 miles).
Fukushima prefecture is north of Tokyo and home to the nuclear power plant that was destroyed by a huge tsunami following an offshore earthquake in 2011.