Japan's emperor addressed the nation Wednesday -- a rare event that only occurs in times of war or national crisis.
Emperor Akihito's speech underlined Prime Minister Naoto Kan's earlier assertion that the country was going through its worst crisis since World War II. And it came on the same day that white smoke and a new blaze at the damaged Fukushima Daiichi's nuclear plant added to radiation concerns in a country grappling with a nuclear crisis.
Even workers who remained at the plant evacuated temporarily as officials said radiation levels there fluctuated.
The developments at the plant are the latest setback for a country struggling to dig its way out of the wreckage and find survivors after last week's devastating earthquake and tsunami.
The fire was discovered Wednesday morning in the northwestern corner of the No. 4 reactor building at the plant, a power company official told reporters. It renewed concern over spent fuel rods sitting in an uncovered pool inside, which would release dangerous radiation if they caught fire.
Meanwhile, the search continued for survivors from the Friday's twin disasters.
By Wednesday afternoon, the National Police Agency reported 3,771 deaths. Another 7,843 people are missing and 2,044 were injured, the agency said. The number of dead is expected to go up as rescuers reach more hard-hit areas.
Shell-shocked survivors huddled in cramped shelters, grieved over lost loved ones and worried about relatives who are missing across villages and towns inundated by the tsunami waves off the east coast of Honshu.
Many crowded at Narita International Airport, trying to get as far away from the nuclear plant as possible.
"We just headed for the mountains directly away from the nuclear power station," Richard Struthers, who lives about 70 kilometers from the Fukushima plant. He said he is "taking no chances" with his baby son.
Boris Suban of Moriya -- about 209 kilometers (130 miles) from the nuclear plant -- decided to travel across the country to Hiroshima Prefecture -- a location he admits is ironic.
'We thought that the reactor is not safe and too near," Suban said. "Plus, if the panic spreads, we will be unable to leave Japan and get the full exposure sitting on our sofa."
The latest concerns at the Fukushima Daiichi plant came a day after another fire there and an explosion at the plant's No. 2 reactor.
Japanese authorities could not rule out the possibility of a meltdown at the troubled reactors. Workers have been pumping sea water into reactors in an effort to prevent further damage.
A meltdown occurs when nuclear fuel rods cannot be cooled, thus melting the reactor core and causing a release of radioactivity. In the worst-case scenario, the fuel can spill out of the containment unit and spread toxic radioactivity through the air and water. That, public health officials say, can cause both immediate and long-term health problems, including radiation poisoning and cancer.
The plant is in Fukushima Prefecture, about 138 miles (225 kilometers) from Tokyo. Officials urged people within 30 kilometers (18.6 miles) of the plant to remain indoors.
Edano said analysts also have their eyes on reactors No. 5 and 6 at the plant, where cooling systems weren't functioning well.
"The temperatures are rising, but we are doing our best to cool (them) down," the chief Cabinet secretary said Wednesday.
Meanwhile, across the country, emergency workers from Japan, foreign governments and international aid groups continued to scour tangled and displaced piles of debris, searching for survivors. At least 91 countries and regions and six international organizations have offered assistance, according to the Japanese foreign affairs ministry.
Public broadcaster NHK has reported that 450,000 people were living in shelters. A teacher in Miyagi Prefecture said many schools had turned into emergency shelters.
Cold weather has increased the hardship for disaster victims and rescuers. Rescuers reported some victims have been exposed to cold weather and water, in some cases for days. Sleet fell in the decimated city of Sendai this week.
Rescue work is also being complicated by the hundreds of aftershocks that have rocked Japan since Friday's quake. The U.S. Geological Survey has reported several quakes with magnitudes of 6.0 or greater, and more than a dozen others greater than 5.0 or greater.
While agencies are working to raise money, donations have been slow to come. The Chronicle of Philanthropy, a newspaper covering nonprofit organizations, says donations to nonprofit organizations have reached about $25 million so far. The total is far below the first four-day totals of other recent natural disasters, including Hurricane Katrina and the crisis in Haiti, it said.
Wide-scale economic problems also loom, though some signs of progress surfaced in the stock market on Wednesday.
Stocks in Japan opened higher Wednesday morning, one day after the nation's main market index suffered one of its biggest drops on record. The Nikkei 225 index, the most prominent measure of Tokyo market stocks, rose 520 points, or 6%, shortly after the market opened.
On Tuesday, the Asian economic powerhouse reeled as stocks plummeted, sending shock waves through global markets.
The massive quake was the strongest in recorded history to hit Japan, according to USGS records that date to 1900.
Amid the massive despair, tales of survival and euphoric relief emerged.
Akiko Kosaka, a student from Japan attending the University of California at Riverside, had lost all hope for her family in Minami Sanriku, the fishing village where more than half of the 17,000 residents are missing and feared dead.
"I didn't think they survived," Kosaka, 20, told CNN during a tearful interview Tuesday. "I cried for three days -- Friday, Saturday, Sunday."
Then a friend in Japan told her about a 45-second YouTube video showing her family home as the only one standing amid the rubble. The video highlighted her young woman holding a sign to a TV news crew saying in Japanese "we are all safe."
The woman was Kosaka's sister.
"I screamed, and my host parents woke up and they thought it was really bad," Kosaka said. "They asked what happened. And I said, 'They survived! ... I couldn't believe it. It's a miracle."