Emperor prays for Japan as radiation halts work to cool reactor (UPDATES) (VIDEO)

YAMAGATA, Japan — Japan's Emperor Akihito made a rare public address on Wednesday saying he was "deeply concerned" about the nuclear crisis facing his country in the wake of a massive earthquake and tsunami.

His comments came as conditions at the country's Fukushima Daiichi power plant, where explosions and fires have hampered efforts to cool overheating reactors, became so dangerous that operations to prevent a nuclear meltdown were temporarily suspended.

Akihito, 77, said he was praying for the safety of survivors of the disasters that are feared to have killed more than 10,000 people, urging them to work together to overcome adversity, the BBC reported.

"People are being forced to evacuate in such severe conditions of bitter cold, with shortages of water and fuel… I cannot help praying that rescue work is done swiftly and people's lives get better, even a little," he said, according to AFP.

The emperor said he was "deeply concerned" about the "unpredictable" situation at the Fukushima power plant, where tens of thousands of people have been evacuated as a precaution against radiation leaks now wafting across the country.

An official at the U.S. Nuclear Regulatory Commission told Congress Wednesday that he believed all the water in the spent fuel pool at the No. 4 reactor at the plant had boiled dry, leaving the fuel rods exposed and bleeding radiation. "We believe that radiation levels are extremely high," he said, according the The New York Times.

A surge in radiation at Fukushima made conditions for workers too dangerous for several hours, Toronto's Globe and Mail reported. Chief Cabinet Secretary Yukio Edano said work on dousing reactors with water could not be continued due to the need to withdraw.

An official for Tokyo Electric Power, which operates the stricken plant, said the workers had withdrawn 500 yards, but were getting ready to go back in, AP reported.

"The workers cannot carry out even minimal work at the plant now," Edano said, according to AP. "Because of the radiation risk, we are on standby."

The Nuclear and Industrial Safety Agency said two workers at the plant were missing after the multiple explosions and fires, Al Jazeera reports. Fifty workers had stayed behind at the plant, "braving radiation and fire," in an effort to cool the reactors and save Japan from a nuclear disaster.

To avoid exposing workers to harm, authorities were turning to other options for injecting water to douse reactors. Police have been asked for help using water cannon, however an earlier plan to drop water from helicopters was abandoned, ABC news reported.

The suspension of operations followed an outbreak of fire at one of the reactors early Wednesday morning, posing the latest setback in a series of disasters that have hit the plant.

A day earlier, an explosion and fire at the plant in northeastern Japan caused large amounts of radiation to leak into the air, intensifying concerns over a possible nuclear catastrophe caused by Friday's devastating earthquake and tsunami. The 9.0-magnitute earthquake damaged the plant's cooling functions.

On Wednesday, the outer housing of the containment vessel at the plant's No. 4 reactor erupted in flames, according to information from the plant's operator.

The company said the fire broke out because Tuesday's fire, which occurred in the fuel storage pond of the same reactor, had not been completely extinguished.

The Tokyo Electric Power Co has been struggling to bring the crisis at the plant under control. The plant, 140 miles northeast of Tokyo, has suffered multiple explosions since Saturday.

The New York Times reports that authorities are particularly worried about pools for spent fuel rods at several reactors at the plant. The rods are radioactive and "potentially as hot and dangerous as the fuel rods inside the reactors," it states. The No. 4 reactor's pool has lost some of the water needed to keep the rods stable.

Late Tuesday, the government said radiation levels had fallen again, somewhat quelling fears. It remains unclear if the new blaze will cause more radiation to spread.

Prime Minister Naoto Kan earlier said that radiation was spreading from four reactors at the nuclear plant. A 15-mile exclusion zone was enforced around the plant as engineers battled to bring overheating reactors under control.

And the 140,000 people living within 20 miles of the plant were ordered to leave the area or stay indoors with the windows shut and the air conditioning off.

Radiation fears have prompted a major exodus from Tokyo, despite reassurances that only low levels of radioactivity were drifting towards the capital. One journalist told Canada's CTV that he was the last person he knew to leave.

The French government on Wednesday told its citizens to leave Japan, warning that the the situation at Fukushima was out of control, Reuters said. It asked national carrier Air France to lay on extra flights to cope with extra demand from French citizens trying to get out.

Meanwhile, continuing aftershocks, some of which have registered as high as 6.0-magnitude, have kept the Japanese on edge.

“I’m really scared. The earthquake on Friday really shook everything here, and nobody knows what’s going to happen at Fukushima,” said a young man working in a clothes shop in Yamagata City, which is in Yamagata Prefecture, one of the worst-hit areas.

“The aftershocks just keep coming. I’ve had enough,” he said.

Yamagata City is located just over the mountains from Sendai, which is in Miyagi Prefecture in northeastern Japan. Sendai was the largest city near the quake's epicenter.

A shell-shocked population becomes more skittish with every tremor, persistent rumbling that would, under normal circumstances, barely register with the northeast's quake-hardened people.

A restaurant in the center of Yamagata city was empty save for two customers today. The waitress said people were scared to leave their homes because of the quake and the fear of radiation, which has been detected as far away as Vladivostock in Russia.

In Yamagata, a sports center is being prepared for evacuees from around the Fukushima plant, even as snow fell heavily Tuesday evening and the city prepared for power outages.

The government began rolling blackouts Wednesday around the country to compensate for the loss of energy from Japan's nuclear power plants, most of which shut down automatically during Friday's earthquake, BBC reports.

The disaster has left more than 500,000 people homeless, and millions of people on the east coast have little food, water or heat.

Despite the difficult situation, however, people here have remained civil.

At long lines for rationed gasoline and limited foodstuffs across the region, there was no jostling for better positions and no arguments.

At a small family-run hotel in the port town of Hitachi, its harbor destroyed, refugees from the devastated areas to the north arrived late into the night Tuesday.

Weary customers who would have likely paid any price for a dry place to lay their head, were given discounts for the lack of running water and the owner's apologized profusely for the lack of running water.

— Additional reporting by Hanna Ingber Win in Mumbai and Barry Neild in London.