Japan: 15,000 dead or missing since quake

Japanese officials said Thursday that more than 15,000 people were either killed or left missing by the devastating earthquake and tsunami which ravaged the country's northeast last week.

Another 387,000 Japanese residents had been forced from their homes and were in temporary accommodation -- the quality of which varied greatly. According to the most recent figures, released by Japan's national police agency, at least 15 people have died in refugee camps.

Complete coverage: Disaster in Japan

A massive 9.0 magnitude quake struck Japan's east coast on Friday, sending a towering wall of water, 40 feet high in some areas, tearing into the country with devastating force.

As search and rescue crews from Japan and around the world struggle to deal with the scope of the physical disaster in the hard-hit Miyagi prefecture, the threat of a nuclear meltdown looms large at a power plant in nearby Fukushima.

Japan's military was using heavy-lift Chinook helicopters Thursday to dump tons of seawater onto reactors at the Fukushima Dai-ichi plant to try and prevent spent nuclear fuel and the active reactors themselves from reaching a critical level of overheating. The plant's normal cooling system, and the backup systems, failed after the tsunami slammed into the plant almost a week ago.

America's nuclear regulatory chief told lawmakers on Wednesday that he remains deeply concerned about the situation at the Fukushima plant, saying he believed the level of radiation immediately around the complex was likely "extremely high" - likely lethal in a relatively short period of time.

The Obama administration authorized the first government-chartered evacuation flights for American citizens out of Japan on Thursday.