(With Photo) TOKYO, May 24 (KUNA) -- Japan's Tokyo Electric Power Co. (TEPCO) on Tuesday confirmed for the first time that fuel meltdowns may have occurred at two more reactors at its troubled Fukushima Daiichi nuclear power plant within a few days of the March 11 massive earthquake and tsunami.

"New analysis show that fuel rods in the No. 2 and No. 3 reactors may have melted, but both reactors are now being cooled and in stable conditions," a TEPCO spokesman told a press conference.

He said the meltdown in the No. 2 reactor took place about 101 hours after the quake, and 60 hours in the No.3 reactor, respectively.

Tuesday's announcement means all three active reactors at the six-reactor Fukushima complex are believed to have suffered meltdowns. The utility already confirmed earlier this month a meltdown of fuel rods at the No. 1 reactor.

"Most of the fuel is believed to have melted down and collected at the bottom of the pressure vessels containing them, a similar condition of the No. 1 reactor," the spokesman said, adding that damage at the No. 2 and No. 3 reactors are less critical than at the No. 1 unit.

The utility also maintained its view that the accident was caused by the giant tsunami, not by the magnitude-9 earthquake, saying the tsunami disabled the plant's power sources and key cooling systems, leading reactors to overheat and radiation leaks.

Also on Tuesday, Industry minister Banri Kaieda said the government decided to set up a third-party panel to investigate the cause and handling of the world's worst radiation crisis since the 1986 Chernobyl catastrophe.

TEPCO said last week it still sticks to its timetable of bringing radiation crisis under control by January.