Japan earthquake

• Washington has expressed alarm over the crisis at the Fukushima Daiichi nuclear complex in Japan, which has experienced a series of explosions and fires since being severely damaged by the huge earthquake and tsunami last week. Senior US nuclear official Gregory Jaczko said he thought the spent fuel rods from one of the reactors were now exposed
• Japanese military helicopters have dropped four loads of water on the stricken plant, trying to avert a full meltdown. Plant operators say they are trying to finish a power line which could bring the plant's cooling systems back online.
• Some US military personnel in Japan have received potassium iodide tablets to help counter any radiation exposure and the US has urged American citizens living within 80km (50 miles) of the Fukushima complex to leave; Japan's own exclusion zone is only 20km
• The number of confirmed dead and missing now stands at nearly 13,000 while some 450,000 people have been staying in temporary shelters amid sub-zero night-time temperatures
• Despite the crisis in Japan, the yen has risen close to its highest value against the US dollar since World War II. The BBC business reporter says the yen is being driven by market belief that Japan will need to repatriate some of its huge foreign holdings to pay for reconstruction
• Live page reporter: Matthew Davis
• All times in GMT

0209 The power supply to the stricken Japanese nuclear plant could partially resume in the afternoon, the Kyodo agency reports

0201 Water spraying operations have been temporarily suspended and helicopters have left the area of the Fukushima Daiichi plant, NHK reports. A Tokyo police unit is set to use water spray vehicles to continue cooling operations at Reactors 3 and 4. The Japanese defence minister is about to give an update on how the water drops went.

0150 Helicopters are rotating in their mission to dump water on Reactor 3, gathering seawater from close to the Fukushima Daiichi plant. Four water drops are so far thought to have taken place but targeting of the spray is proving difficult, NHK reports .

0143 The Daily Yomiuri tweets: "According to govt estimates, of 1.76 million meals shipped to disaster-hit areas, 1.29 million had NOT reached shelters as of yesterday."

0138The Bank of Japan has pumped an extra five trillion yen into the money markets which have been shaken by the quake, tsunami and unfolding nuclear power plant drama. The move raises its total funds injected since Monday to 33 trillion yen. In early trading on Thursday the benchmark Nikkei index has plunged more than four percent.

0128Around 10m households in the Kanto area around Tokyo are being affected by rolling blackouts for the fourth day running to cover power shortages, the Tokyo Electric Power Co says - Kyodo.

0121The helicopters are gone now, in order to minimise the crews' exposure to radiation - NHK.

0118That's four loads of water dropped - NHK.

0117A lead plate is attached to the bottom of each chopper and the crew are wearing protective suits - NHK.

0115These are CH-47 Chinook helicopters. Each would normally have a crew of three: pilot, co-pilot and flight engineer.

0114Eleven water cannon trucks are on their way to the plant - NHK.

0112Let's recall what top US nuclear official Gregory Jaczko had to say about the risks facing the crews fighting to cool down the reactors: "It would be very difficult for emergency workers to get near the reactors. The doses they could experience would potentially be lethal doses in a very short period of time."

0110And US nuclear experts believe there is no water left in Reactor 4's cooling pool, meaning radiation levels are extremely high there.

0108The reason Reactor 3 got the first shower is because of escaping smoke or steam, indicating water evaporating from the cooling pool, Reuters news agency notes.

0106This is no easy task for the chopper crews. They can't afford to hover above the reactors because of the radiation so they are making the drops in passing.

0104Just seen a third load of water spraying from a chopper. Seems it was aimed at Reactor 4.

0102It was feared yesterday that Reactor 3 might have released radioactive steam due to damage to its containment vessel.

0059Can see a white curtain of water dropping on the reactor from a helicopter, live on NHK TV.

0057Suzanne, from London, writes: "I have heard the foreigners leaving Japan referred to as fairweather friends but I think it is important not to be judgemental. If you don't speak Japanese and don't have family in the country then you are pretty isolated. My husband feels so guilty for leaving Tokyo but he is now working remotely from Shanghai and on the plus side he is not using up their precious electricity and supplies."

Have Your Say

0057There are two helicopters now working above Reactor 3 - NHK television. Each is capable of dropping 7.5 tonnes of water, it says.

0054Toby Memmott, from Tokyo, writes: "A lot of people are leaving Tokyo and even Japan because they are worried about radiation exposure. The truth is there is widespread panic among the foreigners here that is fuelling a media frenzy that in itself is fuelling fear and unrest with the foreigners: a Catch 22 situation. The worst thing we can do right now is abandon the Japanese people and their economy. The ones who decide to stay are having to deal with an almost doubled workload because so many have left or are leaving. Those who leave will be able to come back in two to three weeks to their job like nothing ever happened. There are so many people in the north who lost everything but given a choice to leave Japan I don't think they would. Be smart and support Japan, don't just run away."

Have Your Say

0052More helicopters are on their way to dump water on the reactor - NHK television.

0051A Japanese army helicopter is now dropping water on Reactor 3 - Kyodo.

0048Japan's defence ministry gives the go-ahead for spraying water on the reactor from helicopters - Japan's Kyodo news agency.

0044Japanese Economics Minister Kaoru Yosano says the yen's jump is driven by speculative moves, denying that Japanese insurers' currency repatriation is behind the surge - Reuters.

0043The Bank of Japan offers to inject a further 5tn yen ($61bn) into the banking system, continuing its effort to calm markets in the wake of the yen's spike to a record high against the dollar, Reuters reports. This comes on top of a total of 28tn yen already offered in same-day operations this week.

0032Japanese shares have now slumped more than 4% in early trade - AFP.

0030A Tokyo police unit is preparing to use water cannon this morning to cool down Reactor 4 at the Fukushima Daiichi nuclear power plant, Japanese broadcaster NHK reports. The police say they are acting at the government's request.

0022Japanese Finance Minister Yoshihiko Noda says he will closely watch the market. "Market moves have been nervous amid speculation while trade has been thin," he tells reporters.

0020 The benchmark Nikkei index fell 3.6% in early trading.

0013Nikkei futures traded on the Osaka Securities Exchange opened down 6.3% - Reuters. Ten-year JGB futures opened up 0.63 points at 140.35.

0012Japanese shares opened 1.98% lower today, AFP news agency reports. The benchmark Nikkei index fell 180.37 points to 8.913,35 in the first minutes of trading after rising more than 5% on Wednesday.

0005Just a reminder that the focus of the nuclear concern is on the Fukushima Daiichi power station and its six reactors (Fukushima Dai-ni, a nearby station with four reactors, has reportedly been cooled down safely). With the cooling system damaged by the quake, accidents have been occurring since Saturday in Reactors 1-4. One of the most worrying situations is in Reactor 4, which along with 5 and 6 had been shut down for planned maintenance before the quake.

0004It's 0904 local time after another freezing night in the north. Nearly half a million people passed it again in temporary shelters such as school gyms. The search for survivors along the tsunami-ravaged north-eastern coast goes on though nearly a week has passed since the quake. More than 8,000 people are still listed as missing and every day brings to light new bodies. Meanwhile, anxiety over radiation escaping from the crippled nuclear reactors in Fukushima Prefecture continues.

0003Welcome to the seventh day of our live coverage of Japan's earthquake disaster. Stay with us for the latest updates - reports from our correspondents on the ground, expert analysis and your reaction from around the world. You can contact us via e-mail, text or twitter. We'll publish what we can.