Japan's nuclear regulatory agency said it raised the alert level at the Fukushima plant to 7, on par with the 1986 Chernobyl disaster in Ukraine. The Fukushima plant was crippled when a 9-magnitude earthquake and tsunami struck the island nation March 11.
Plant operator Tokyo Electric Power Co. apologized for being unable to stop the radiation leak, pointing to the possibility total emission of radioactive substances eventually may eclipse the Chernobyl incident.
The IEA wrapped up a 10-day conference on nuclear safety in Austria that included assessments of the nuclear emergency in Japan.
"As a result of the Japanese disaster, the contracting parties are carrying out safety reviews of their nuclear installations, including re-examining the nuclear power plants' safety measures that defend against extreme external events," the IEA said in a statement.
The parties to the IEA conference in Vienna reaffirmed their commitment to nuclear safety through global cooperation.
Delegates said they agreed to revisit nuclear safety issues using lessons learned from the Fukushima accident but stressed it was too early for any grand assessments.
"It is understood that the lessons learned process cannot be completed until sufficient additional information is known and fully analyzed," a joint statement from the delegates read. "Japan has committed to provide this information as soon as possible."