Following are main developments after a massive earthquake struck northeast Japan on Friday and set off a tsunami.
* Japanese television pictures show white smoke coming from a quake-crippled nuclear facility. But public broadcaster NHK says it is unclear if the smoke is coming from the No.4 reactor of the Fukushima Daiichi nuclear plant, where fire had broken out earlier in the day.
Earlier, NHK said flames were no longer visible at the No.4 reactor of the Fukushima plant, 240 km (150 miles) north of Tokyo.
- Nuclear power plant operator Tokyo Electric Power says it is considering dispersing boric acid, a fire retardant, over the Fukushima Daiichi plant's No. 4 reactor from a helicopter.
- Winds over a radiation-leaking nuclear power plant in northern Japan will blow from the north along the Pacific coast early on Wednesday and then from the northwest towards the ocean during the day time, the Japan Meteorological Agency says.
- Japan's benchmark Nikkei average rises more than 6 percent in early trading on Wednesday after suffering its worst two-day rout since 1987.
- Tokyo Electric Power Co (TEPCO) , operator of the Fukushima power plant damaged in the quake, says one of two blasts blew two holes in the building housing reactor No. 4, meaning spent nuclear fuel was exposed to the atmosphere. It says helicopters may dump water to cool the spent-fuel pool.
- The radiation level in Tokyo was 10 times normal on Tuesday evening, but there was no threat to human health, the city government says.
- People within a 30-km radius of the nuclear facility urged to stay indoors.
- Plant operator has pulled out 750 workers, leaving just 50, and 30-km no-fly zone has been imposed around the reactors.
- Food and water in short supply in parts of the northeast. hundreds of thousands have been evacuated, shelters are packed.
- Rolling power blackouts will affect 5 million households on Tuesday, TEPCO says.
- Some residents leave the capital. Others stock up on food.
- Death toll is expected to exceed 10,000, and rescue workers are continuing to search coastal cities for survivors.