As foreign rescue workers combed debris to locate victims of Japan's quake and tsunami, countries offered further aid from field hospitals to atomic physicists to address an unfolding nuclear crisis.
Fire-fighters, sniffer dogs, clothing and food have been proposed in an outpouring of solidarity with Japan, with offers pouring in from nearly 70 countries, U.N. officials said.
Even the poor southern Afghan city of Kandahar announced it was donating $50,000 to the "brothers and sisters" of Japan.
"I know $50,000 is not a lot of money for a country like Japan, but it is a show of appreciation from the Kandahar people," Kandahar Mayor Ghulam Haidar Hamidi told Reuters.
Japan has pledged $5 billion in aid to Afghanistan over the next five years, more than one-third of the total $13 billion in foreign aid pledged to the country over the next five years.
Japan fought on Sunday to avert a disastrous meltdown at three earthquake-crippled nuclear reactors as estimates of the death toll from the tsunami that charged across its northeast rose to more than 10,000.
Pakistani Prime Minister Yusuf Raza Gilani said Pakistan would extend all possible assistance to Japan.
"I have written a letter and we have offered them, if they need them, field hospitals, whatever assistance we can extend," Gilani told reporters in the central Pakistan city of Multan.
Nearly a dozen countries have sent rescue workers following Japan's request, including teams from Australia, China, and the United States, the United Nations said. Seventeen more rescue teams including one from Israel were on standby.
"This is a country that regrettably is very experienced at this. But we all can see the scale of the devastation," U.N. humanitarian chief Valerie Amos told Sky News.
"I'm hearing reports that there are many parts of the country that even the search and rescue teams or the Japanese defence forces on the ground aren't able to get to those places because of fears of aftershocks," she said.
China's 15-member rescue team arrived in Japan on Sunday, state news agency Xinhua said, bringing with them four tonnes of equipment for search and rescue operations, including their own power supply and telecommunications equipment.
Australia's government has offered self-contained field hospitals and disaster victim identification teams. Two military transport aircraft carrying search and rescue teams, as well as sniffer dogs, had already left for Japan.
Britain has sent 59 fire service search and rescue specialists, along with two rescue dogs and a medical support team. The team will take up to 11 tonnes of specialist rescue equipment, including heavy lifting and cutting equipment.
Britain has also said that it would send nuclear physicists if requested.
Japanese officials worked desperately to prevent the fuel rods in the damaged plants from overheating after radiation leaked into the air. The government said a building housing a second reactor was at risk of exploding after a blast blew the roof off a different plant the day before.
But the World Health Organisation said that the public health risk from the worst nuclear accident since the Chernobyl disaster in 1986 remained "quite low".
"There is no evidence to suggest otherwise," WHO spokeswoman Christy Feig told Reuters in Geneva.
Japan had not sought deployment of the U.N. agency's network of radiation experts known as REMPAN (Radiation Emergency Medical Preparedness and Assistance Network), she said.
"There is no need to go in, everybody is still in a holding pattern," Feig said.
Teams from Medecins Sans Frontieres (Doctors Without Borders) have reached Sendai, where they found "stark" damage.
"Although the medical situation in Sendai appears to be under control, the population has needs", Mikoko Dotsu, MSF assessment coordinator said in a statement.
"At the moment, there is very little electricity and no water supply. People need food, blankets, and water. These needs are bigger than medical needs at the moment," Dotsu said.
The Indian government is to ship planeloads of woollen blankets to affected areas to help fight cold weather conditions, Foreign Secretary Nirupama Rao said.
Japan has declined Taiwan's offer of rescue team for now but has requested material aid including generators clothing and food, Taiwanese officials said. Taiwan has donated $3.3 mln and has rescue and medical teams ready to go if Japan requests them.