The blast was weaker than many experts has expected.
WASHINGTON (AP) -- U.S. spy agencies confirmed North Korea's nuclear test Monday, even as Secretary of State Condoleezza Rice declared that U.N. sanctions prove the world is united in opposing Pyongyang's nuclear ambitions.
Such strong opposition should be a warning to Iran, too, said Rice, who is leaving this morning for an Asian trip that is expected to be dominated by the nuclear issue. She will visit Japan, South Korea, China and Russia.
Providing the government's first definitive confirmation that North Korea detonated a nuclear device one week ago, National Intelligence Director John Negroponte's office said in a statement that air samples collected Wednesday showed evidence of radioactivity. That verified North Korea's claims.
"The explosion yield was less than a kiloton," the statement said, smaller than many experts had expected.
Each kiloton is equal to the force produced by 1,000 tons of TNT. An intelligence official said the North Korean device was believed to be roughly the equivalent of 200 tons of TNT, suggesting to analysts that it was probably a partial failure. Experts in and out of government had anticipated a detonation of at least several thousand tons.
The official spoke on condition of anonymity because of the sensitive situation with Pyongyang.
At the State Department, Rice said the world "has responded calmly and firmly" to the test.
"North Korea cannot endanger the world and then expect other nations to conduct business as usual in arms or missile parts," Rice said, previewing her message for the Asia trip. "It cannot destabilize the international system and then expect to exploit elaborate financial networks built for peaceful commerce."
She said Iran -- another government accused of running an illicit nuclear program -- should pay attention to the global reaction. That would include the U.N. Security Council's sanctions adopted Saturday, aimed at making life difficult for the North Korean government and its weapons proliferation business.
"The Iranian government is watching, and it can now see that the international community will respond to threats from nuclear proliferation," said Rice, who added that she believes the Security Council will begin working on a sanctions resolution against Iran this week. "The Iranian government should consider the course that it is on."
The United States, North Korea and seven other nations are now believed to have nuclear arms. Yet North Korea's unpredictable behavior makes its nuclear advancements particularly worrisome to its neighbors and the international community.
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