Updated from 12:01 p.m. EDT with information regarding the Fukushima Dai-ichi nuclear-power plant.
) -- The Fukushima Dai-ichi nuclear-power complex in Japan suffered a third explosion and Japanese officials warned that a critical reactor container, which keeps radioactive materials from leaking, may have been damaged, according to reports.
International Atomic Energy Agency director general Yukiya Amano said that right now it is hard to predict how the current nuclear crisis in Japan will develop because there are so many unknown factors,
"The problem is very complicated, we do not have all the details of the information so what we can do is limited," Amano said in a news conference on Tuesday. "I am trying to further improve the communication."
The nuclear emergency in Japan escalated on Tuesday after a build-up of hydrogen caused a third hydrogen explosion at the Fukushima power plant in two days.
The blast at Unit 2 damaged the reactor's main containment shell and "may have affected the integrity of its primary containment vessel," the International Atomic Energy Agency said.
The IAEA also reported that a fire broke out in the reactor's fourth unit late Monday night, releasing radioactivity "directly into the atmosphere" at the rate of up to 400 millisievert per hour.
"The level [of radiation] seems very high, and there is still a very high risk of more radiation coming out," Prime Minister Naoto Kan said in a brief address to the nation,
The Wall Street Journal
reported. "We will do our utmost to prevent further spreading of radiation leaks. I sincerely urge everyone in the nation to act calmly."
With the risks of leaks rising, Japan ordered 140,000 people, or those living with 19 miles of the Dai-ichi complex, to seal themselves indoors Tuesday,
The Associated Press
"Please do not go outside. Please stay indoors. Please close windows and make your homes airtight," Chief Cabinet Secretary Yukio Edano told residents in the danger zone,"
reported. "These are figures that potentially affect health. There is no mistake about that."