Japan's Prime Minister at the time of the Fukushima nuclear crisis apologized Monday, May 28 and said the government and its push for nuclear energy bore most of the responsibility for the disaster, AFP reports.

"The nuclear accident was caused by a nuclear plant which operated as national policy," Naoto Kan told a parliamentary inquiry into the cause of the worst nuclear accident since Chernobyl in 1986.

"I believe the biggest portion of blame lies with the state," said the former premier, who has come out strongly against nuclear power since the Fukushima disaster in March last year.

"As the person who was in charge of the country at the time of the accident, I sincerely apologize for my failure to stop it," said Kan, who stepped down in September after 15 months in office.

Kan attacked Tokyo Electric Power (TEPCO) for its failure to keep the government informed about the accident.

"I was thinking it was a battle against an invisible enemy. I thought, if the situation called for it, we might have to risk lives to contain it," he said.