Updates:

10:00 pm EST- In parsing the "bleak" Congressional testimony of Gregory Jaczko, the chairman of the U.S. Nuclear Regulatory commission, earlier today, The New York Times finds his most "startling admission" to be that the fuel rods at the No. 4 reactor are exposed to the air. The rods have been "bleeding radiation into the atmosphere."

9:55 - Reuters reports that the Japanese nuclear agency "says radioactivity levels continue to decline" at the plant.

9:45 - "Water was dropped from helicopters Thursday morning [Tokyo time] over two nuclear reactors at the Fukushima Daiichi power plant, the first airborne attempts to address overheating inside related to emissions of radioactive material," CNN reports.The first attempt at a water drop was called off yesterday, with "excessive radiation levels" cited.

6:53 - "A 'partial meltdown' occurred at the Japanese nuclear-power plant damaged by explosions," stated U.S. Energy Secretary Steven Chu (via The Wall Street Journal). According to Reuters, Chu also said that the U.S. will deploy equipment to monitor airborne and ground level radiation exposure.

5:29 - Global airline carriers are "scrambling" to keep up with demand of those looking to leave Japan in lieu of the developing nuclear crisis, Reuters reports.

4:40 - Japanese officials are going to try to do another helicopter water drop on Thursday to cool overheating reactors, reports Reuters.

4:04 - "We believe that radiation levels are extremely high, which could possibly impact the ability to take corrective measures,” said Gregory Jaczko, chairman of the United States Nuclear Regulatory Commission, in a Congressional testimony. (via The New York Times)

3:30 - "Authorities battling the nuclear disaster at the Fukushima Daiichi power plant have doubled the number of workers on the site to 100 in an effort to continue cooling the three reactors and the spent fuel pools," the Los Angeles Times notes.

3:07 - From the Tokyo Electric Power Company: "The operator of Japan's tsunami-crippled nuclear plant says it has almost completed a new power line that could restore electricity to the complex and solve the crisis that has threatened a meltdown," the AP reports

2:39 - "U.S. NRC [Nuclear Regulatory Commission] chairman says spent fuel pool at Japan's reactor 4 has no water, radiation levels are 'extremely high,'" Reuters reports.

1:44 - "U.S. recommends U.S. citizens who live within 80km of Fukushima nuclear plant evacuate or take shelter indoors," reports Reuters Flash. Previously, The Guardian noted that "Australia has advised its citizens to consider leaving Tokyo and earthquake-affected areas, but has said its advice is not due to the threat of nuclear contamination."

1:11 - "U.S. Energy Secretary Steven Chu told a congressional committee Wednesday that the situation at Japanese nuclear power plants is 'more serious than Three Mile Island,' but Americans should rest assured that U.S. nuclear power plants are safe," reports CNN.

12:30 - "The US is to fly a spy plane over the stricken Fukushima plant in a bid to get a closer look at the damage [in the reactors], according to Kyodo news." The reconnaissance flight may occur "as soon as Thursday," The Guardian reports.

12:13 - This appears to clarify the IAEA Head's statement (below). Reuters Flash just reported: "IAEA head says core damage at units 1-3 of Japan's quake-hit nuclear plant confirmed, situation very serious."

12:02 pm - The Head of the International Atomic Energy Association says the situation at Japan's Daiichi nuclear power plant is "very serious," reports Reuters Flash.

11:46 - "The site is effectively out of control...In the coming hours there could be further catastrophic events which could pose a threat to the lives of people on the island," European Union's energy chief Günther Oettinger told a European Parliament Committee in Brussels. (via The Wall Street Journal)

11:15 -"In a sign of desperation, the police will try to cool spent nuclear fuel at one of the facility's reactors with water cannon, normally used to quell riots," Reuters reports. Yesterday, a planned attempt to use a helicopter to drop water into a cooling pond was called off because of  "excessive" radiation levels.

10:45 - "Severe damage to the containment vessel of the No. 3 reactor at the Fukushima Daiichi nuclear plant is unlikely, Japan Chief Cabinet Secretary Yukio Edano said Wednesday, according to a Kyodo News service report." (via CNN)

10:21 - Reuters Flash report: "Japan nuclear safety agency: radiation levels outside Daiichi plant spiked about noon but fell back."

10:10 - A revealing example of the miscommunication occurring between TEPCO (Tokyo Electric Power Company) and the media. The Wall Street Journal reports that when a fire broke out yesterday at the Fukushima plant's No. 4 reactor, a reporter asked a TEPCO representative how it began. After initially explaining that the information wasn't available, the TEPCO representative responded two hours later: "Turned out the smoke was coming not from reactor No. 4, but from reactor No. 3."

9:47 EST - Japanese officials have raised the maximum allowable radiation exposure for the remaining workers at the Fukushima plant to "250 millisieverts from 100 millisieverts" saying that the move was "unavoidable due to the circumstances," the AP reports.

Original Post (8:21 EST):

Yesterday, Japanese officials indicated that the situation at the crippled Fukushima Daiichi Nuclear Power Station had begun to stabilize, even as reports detailed radiation exposure among U.S. helicopter crews and leakage of radioactivity "directly" into the atmosphere. On Wednesday, the latest news accounts appear to be painting a grimmer scenario.

The 50 workers remaining at the plant (the rest of the 1,400 were withdrawn earlier by the Tokyo Electric Power Company) briefly had to withdraw from containing the situation because of "surging radiation levels," Reuters reported this morning (the New York Times characterized it as a crisis that "intensified dramatically"). Fears of radiation wafting their way toward Tokyo were also confirmed as "low levels of radiation" were reported in the city.

A planned helicopter water drop that the Japanese government said yesterday it was considering to "drop water into the cooling pond through the damaged roof of the reactor building," (via CNN) has apparently been called off. "After flying a surveillance helicopter to measure the radiation levels above the plant, the government canceled the plan, citing excessive radiation levels, chief government spokesman Yuko Edano said," the Wall Street Journal explained.

140,000 people in the 30 km area surrounding the plant have been warned to stay indoors and close their windows in an effort to limit radiation exposure. But government spokesman Edano stressed that "People would not be in immediate danger if they went outside with these levels. I want people to understand this," Reuters reported.

As the situation evolved since late last week, plenty of observers, notably The Atlantic's Cristine Russell, have cautioned about the "sea of confusing, conflicting and often limited information emanating from sources across the world" about the developments in Fukushima. Part of the reason, as the New York Times noted this morning, is that Tokyo Electric Power "
says it cannot know for sure what is happening in many cases because it is too dangerous for workers to get close to some reactors."

Updating Coverage: