Developing: Another Explosion Rocks Troubled Fukushima Nuclear Reactor

Kyodo:

The sound of a blast was heard Tuesday morning at the troubled No. 2 reactor of the quake-hit Fukushima No. 1 nuclear power plant, the government said.

The incident occurred at 6:10 a.m. and is feared to have damaged the reactor's pressure-suppression system, the Nuclear and Industrial Safety Agency said, citing a report from the plant's operator Tokyo Electric Power Co.

In a news briefing, Tokyo Electric officials confirmed the blast at reactor 2 happened "near the pressure vessel."  They also confirm that some staff at the nuclear power plant are being evacuated while 50 employees are staying behind at the Fukushima plant.  Radioactive materials are feared to be leaking.

Higher radiation levels have been measured in Ibaraki -- south of Fukushima -- suggesting there may be a crack in the reactor's containment dome.

The latest explosion is the third in four days at the Fukushima, amid fears of a meltdown.

Update

Kyodo confirms radiation levels surrounding the Fukushima nuke plant increased dramatically following Monday afternoon's explosion.

The radiation level at the troubled nuclear plant in Fukushima Prefecture shot up to 8,217 micro sievert per hour temporarily Tuesday morning after an explosion was heard at its No. 2 reactor, Tokyo Electric Power Co. said.

The level as of 8:31 p.m. was more than eight times the 1,000 micro sievert level to which people are usually exposed in one year.

Tim Trevan, a former U.N. weapons inspector, offered his insight on reports out of Japan. Trevan says the latest explosion means there’s a problem getting water in to cool down the fuel rods:

FNC's Shep Smith also heard new earthquake warning sirens sounding off in Tokyo:

Update 10:38 p.m.

The New York Times reports:

Japan faced the likelihood of a catastrophic nuclear accident Tuesday morning, as an explosion at the most crippled of three reactors at the Fukushima Daichi Nuclear Power Station damaged its crucial steel containment structure, emergency workers were withdrawn from the plant, and much larger emissions of radioactive materials appeared immiment, according to official statements and industry executives informed about the developments.

With the latest explosion, NBC's Tom Costello predicts a situation eclipsing Three Mile Island:

Japanese government officials warn that a fourth reactor has caught fire and residents within 20 kilometers of the plant should stay inside to minimize their risk of getting radiation sickness.

Japanese police say the official death toll stands at 2,414, but worry at least 10,000 are dead.

Update 11:14 p.m.

Japan's Chief Cabinet Secretary Yukio Edano says: "Now we are talking about levels that can impact human health. I would like all of you to embrace this information calmly. These are readings taken near the area where we believe that the release of radioactive substances is occurring. The further away you get from the power plant or reactor the value should go down".

Developing...