News reports say Japan has decided to raise the severity level of the crisis at its tsunami-stricken nuclear power plant to 7 _ the highest level and equal to the 1986 disaster at Chernobyl in the former Soviet Union.

Quoting sources at Japan's Nuclear and Industrial Safety Agency, Kyodo News agency and public broadcaster NHK both said Tuesday that NISA would raise the severity level of the nuclear radiation disaster at the Fukushima Dai-ichi plant to 7 from the current 5.

NISA spokesman Minoru Oogoda declined to confirm the reports.