The United States said there is no danger from a one-megaton nuclear bomb that fell off an aircraft carrier in 1965 and which still lies on the Pacific Ocean floor 80 miles from a Japanese island.

"It was 200 miles from Okinawa. It was 80 miles from the nearest point of land. It was way out to sea, in international waters, and the weapon went down in 16,000 feet of water," said Defense Department spokesman Dan Howard."There was no danger to anyone other than the pilot of the aircraft in this incident," he said Tuesday. "There was not then, there is not now."

The bomb was a one-megaton B43 hydrogen device with an explosive power 70 times greater than the bomb the United States dropped on Hiroshima during World War II.

It was the first time the Pentagon has acknowledged that the bomb was lost as close as 80 miles to Japan's Ryukyu island chain and it came a day after the environmental group Greenpeace released newly obtained records showing the accident was much closer to land.

The Pentagon first disclosed the accident in a 1981 report that said a Navy A-4 attack jet carrying a nuclear bomb rolled off an elevator of the aircraft carrier USS Ticonderoga in the Pacific Dec. 5, 1965, and fell into the sea.

"The pilot, aircraft and weapon were lost," the document said. "The incident occurred more than 500 miles from land."

Howard said the distance of 500 miles "from land" was later corrected in a State Department document to "500 miles from the Asian mainland." He admitted that the report never mentioned the bomb being 80 miles from an island.

"The report was not complete. There was no cover-up here," he said.

The attack jet that was lost overboard was preparing for training, which is occasionally done with nuclear weapons, Howard said.

"In this case, the belief was then and still is that the (nuclear) weapon poses no threat to the environment. It is designed to be inert, during storage, handling and transport," he said.

No attempts were made to recover the weapon, he said, adding that the United States did not have the ability to reach the depth of 16,000 feet in 1965 and that he was uncertain the military had the ability to do it now.