A day after it was learned that Tokyo Electric was late in reporting the meltdowns in Fukushima in March 2011, a senior official from the U.N.'s nuclear watchdog on Wednesday urged Japan to build emergency response centers that can sufficiently withstand disasters at nuclear power plants.

Juan Carlos Lentijo, deputy director-general of the International Atomic Energy Agency and head of its department of nuclear safety and security, said a so-called seismically isolated building at the Fukushima No. 1 Nuclear Power Station "was instrumental for conducting mitigation operations" during the triple core meltdown there in March 2011.

"I think this is one of the major lessons from Fukushima," he said in an interview.