Days after an earthquake and tsunami devastated a huge swath of Japan, the nation struggled with immediate fears of a nuclear disaster and longer-term worries about stabilizing the nation and assisting millions of people in need of immediate aid.

Powerful aftershocks kept survivors on edge, as up to 450,000 people crammed into makeshift evacuation centers across the country, waiting for food, shelter and a return to some sense of normalcy. Millions of people spent a fifth night with little food, water or heating in near-freezing temperatures and snow as they dealt with the loss of homes and loved ones.

Meanwhile, officials from Tokyo Electric Power Co. said that a new fire had broken out in a reactor at the company's crippled nuclear power plant in Fukushima. Spokesman Hajimi Motujuku said the blaze erupted early Wednesday in the outer housing of the reactor's containment vessel. Firefighters were trying to put out the flames.

Some residents in northeast Japan ignored a government warning Tuesday to stay indoors and fled from the area of the nuclear power plant, where elevated levels of radiation escaped after a third explosion.

Chief Cabinet Secretary Yukio Edano asked people in a 19-mile radius around the stricken Fukushima-Daiichi plant to "please stay indoors. Please close windows and make your homes airtight." Earlier, the government had ordered the evacuation of the area within 12 miles of the seaside plant.

Edano's advice, which affected about 140,000 people living near the plant, was echoed by Prime Minister Naoto Kan. The prime minister appeared on television Tuesday to deliver a grave update on the situation at the plant, located about 140 miles northeast of Tokyo.

Kan acknowledged that radiation around the plant had spread and "the level seems very high."

He said he wanted to talk to the Japanese people about the crisis and asked them to "please listen to my message calmly.

"The people at the power plant are carrying out [an] operation to inject water to cool the reactors," he said. "They are putting themselves in a very dangerous position. So, in that sense, we hope they can prevent further radiation leakage."

Radiation Levels Rise

Tokyo Electric said radiation levels in a single hour outside the plant had reached the equivalent of more than three years of naturally occurring radioactivity.

A state of emergency was declared at Fukushima No. 1 after it suffered damage in Friday's magnitude 9.0 quake and tsunami, raising questions about the safety of such plants in coastal areas near fault lines and adding to global jitters over the industry.

Officials said 70 workers remained at the complex, struggling with its myriad problems. The workers, all of them wearing protective gear, are being rotated in and out of the danger zone quickly to reduce their radiation exposure.

An additional 800 staffers were evacuated. The fires and explosions at the reactors have injured 15 workers and military personnel, and exposed up to 190 people to elevated radiation.

Doualy Xaykaothao, reporting for NPR from Koriyama, 40 miles to the west of the plant, said cars were lined up to the horizon as people tried to enter the city and escape the area surrounding the facility.

"Obviously, the prime minister's statements were not being heeded," Xaykaothao said. While the exodus appeared calm, "people are scared," she said.

One woman in Koriyama, who gave her name only as Reiko, told NPR she and her family had were among those who fled the coastal area near the power plant.

"According to the news, the government said just live inside the house," she said. "But I cannot believe it."

"The people that I have been speaking to today, who have come from the shore, who have come from the areas near the nuclear power plant, they're saying their worst nightmares are happening," she said. "When they moved to this area, they were told by the government that there would be no fear, no concerns that an earthquake of this magnitude would occur."

Explosions, Fires At Reactors

There was an explosion at a third reactor at the facility Tuesday and fires at a fourth on Tuesday and early Wednesday. Japanese officials told the International Atomic Energy Agency that the first reactor fire was in a storage pond and that "radioactivity is being released directly into the atmosphere." Long after the fire was extinguished, a Japanese official said the pool, where used nuclear fuel is kept cool, might be boiling.

"We cannot deny the possibility of water boiling" in the pool, said Hidehiko Nishiyama, an official with the Ministry of Economy, which oversees nuclear safety.

The cause of the second fire was not immediately known.

The radiation fears added to the catastrophe in Japan that began last week with the largest earthquake ever recorded in the country and a deadly tsunami that followed minutes later.

The confirmed death toll is around 3,300 and thousands more are missing. Many believe the number of fatalities could climb to 10,000 or more in the coming days. Millions of survivors were enduring a fifth night with little food, water or heating in near-freezing temperatures. Up to 450,000 people were in temporary shelters.

Humanitarian Efforts

At one of the main evacuation centers in the city of Sendai, close to the epicenter of Friday's quake, two men broke up wood to put on the fire, where food is made for the hundreds of evacuees.

"We have some food and water to boil, but we don't have much," Matsumo Ito, 60, one of several volunteers at the center, told NPR.

Ito described the government's aid efforts as useless.

"They haven't even brought us anything yet. And this is in Sendai, the biggest city of the region," he said.

But some help had started to arrive by Tuesday, both from Japanese and foreign relief teams. A group of South Koreans in bright yellow vests stood in the lobby of one of the only hotels still open in Sendai.

"Today we want to buy some food," said Yi Woo Jong, the group's spokesman. "But we will try to get some food and we will try to get that food to the people."

But many local residents who can afford to have already left the area, heading for the airport for flights south toward Tokyo or other parts of Japan.

In Ishinomaki, about 25 miles northeast of Sendai, Patrick Fuller, a spokesman for the International Federation of Red Cross, said Tuesday that the tsunami had "engulfed half" of the coastal city.

In a memo written from the town, Fuller wrote that "many lie shivering uncontrollably under blankets. They are suffering from hypothermia having been stranded in their homes without water or electricity."

In another statement on Tuesday, the ICRC said the Japanese Red Cross said it had handed out more than 65,000 blankets and mobilized special helicopter teams to evacuate people from rooftops.

In a report issued Tuesday, the U.N. Office for the Coordination of Humanitarian Affairs, said nearly 416,300 had been evacuated from the earthquake and tsunami affected provinces — nearly half in worst-hit Miyagi prefecture, about 130,000 in Fukushima, 46,000 in Iwate and tens of thousands more in Ibaraki, Tochigi and Aomori prefectures.

The agency quoted national media as saying some 15,000 people are still missing, but USAID has put the figure much lower — at about 3,000.

More than 200 rescue crews from the U.S. and Britain poured Tuesday into the coastal city of Ofunato, finding little but rubble and people looking for lost possessions. Whole city blocks lay flattened. A yacht came to rest atop the remains of a two-story gas station.

U.S. Navy ships and aircraft continue to support search and rescue operations and conduct aerial surveillance of the devastated area, but the Navy said it was sending some of its ships to operate off the country's west coast instead of the east to avoid the radiation hazards presented by the Fukushima plant.

Meanwhile, the 7th Fleet recommended that U.S. service members and their families stationed at two bases in Japan limit outdoor activities after low levels of radiation were detected.

The measures are "strictly precautionary in nature," the Navy said in a statement.

"We do not expect that any United States federal radiation exposure limits will be exceeded even if no precautionary measures are taken," it said.

Japan hasn't seen such hardship since World War II. The stock market plunged for a second day and a spate of panic buying saw stores running out of necessities, raising government fears that hoarding may hurt the delivery of emergency food aid to those who really need it.

With snow and freezing temperatures forecast for the next several days, shelters were gathering firewood to burn for heat.

The Bank of Japan, the country's central bank, injected 3.5 trillion yen ($43 billion) into markets on Wednesday. That came after injections totaling 23 trillion yen ($283 billion) over the past two days. The action is aimed at supporting financial markets that plunged after Friday's magnitude-9.0 earthquake and tsunami.

Initial estimates put repair costs in the tens of billions of dollars, costs that would likely add to a massive public debt that, at 200 percent of gross domestic product, already is the biggest on a percentage basis among industrialized nations.

Foreigners Evacuating

China on Tuesday became the first government to organize a mass evacuation of its citizens from Japan's northeast, while Austria announced it was moving its embassy to Osaka from Tokyo after low levels of radiation were detected in the Japanese capital.

The Chinese Embassy in Tokyo said on its website that it was preparing to evacuate its citizens from Miyagi, Fukushima, Ibaraki and Iwate prefectures "due to the seriousness of and uncertainty surrounding the accident at the Fukushima nuclear plant."

Other foreigners were leaving of their own accord.

At Fukushima airport, Los Angeles resident Nastassja Vidiro said she was not particularly concerned about the radiation but was nonetheless leaving.

"We are just going by what the government is saying. They're saying that we are out of the radius, so just don't go outside. So, I think we're fine. I think everything's OK," she told NPR.

Rob Gifford in Sendai, Doualy Xaykaothao in Koriyama, and Dan Charles in Washington contributed to this report, which contains material from The Associated Press

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