The South Korean government revealed the secret nuclear research on key ingredients for nuclear weapons in a series of embarrassing public admissions over the past week.

The research, conducted as recently as 1982, is the subject of an investigation by the International Atomic Energy Agency.

"I was surprised," Rumsfeld told an audience at the National Press Club here.

"It does not make any difference at all in terms of the security situation on the peninsula," he said.

"And I would certainly doubt that the current government has any clandestine nuclear capability in South Korea. We know that the North Koreans have announced that they do," he said.

A State Department spokesman earlier said the United States did not regard the South Korea research as nuclear weapons activities, only "laboratory experiments."

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