He particularly credited an intelligence-gathering network within his department for helping him conclude confidently that the blast was not a nuclear explosion.

Powell cited the North Korean example at a Senate hearing Monday to drive home his point that attempts to revamp the American intelligence community should take into consideration the unique role of the State Department's Bureau of Intelligence and Research intelligence, commonly known as INR.

He said that "within a short period of time" INR was able to provide him all the information he needed to make a judgment on the North Korean explosion.

"I felt confident in going on television yesterday morning, on talk shows, and saying, "No, it was not a nuclear explosion," Powell said.

North Korea's foreign minister Paek Nam-Sun said Monday that the explosion, which triggered fears of a nuclear test, was a harmless demolition blast linked to a hydro-electric power project.

"When the stories broke over the weekend about some explosion taking place in North Korea and some speculation as to whether it was or was not a nuclear explosion, my instincts told me it was not a nuclear explosion," Powell told the Senate committee on government affairs.

"It was not in a place we would have expected it and so I was immediately skeptical," he said.

Powell said INR had kept him abreast of developments over the blast all day Sunday.

"First thing this morning when I got to the office at 6:35, material was waiting from INR; knowing not just whether it happened or didn't happen, but knowing what my specific needs were to deal with that situation," he said.

More than an hour later, he said South Korean foreign minister Ban Ki-Moon called him "to share notes and talk about what's happening in the area of nuclear weapons development in North Korea.

"And so INR knows what my diplomatic needs are, as well as my information, intellectual and intelligence needs are."

When Democratic Senator Joseph Lieberman asked Powell whether the United States had "adequate satellite-based imagery" and if he had "fullest access" to all intelligence information available to the US government on North Korea, the secretary of state said: "To be precise, it did."

Powell said the whole US intelligence community should in fact be praised for keeping track of developments in North Korea.

"It's what the rest of the intelligence community did that was brilliant that INR was able to draw upon, analyze, look at, and give me what they knew I would need," he said.

Powell however expressed caution when asked if there was a need to create specific intelligence gathering centers on North Korea and weapons of mass destruiction.

"I think others should talk to whether or not there a need for all of these centers. But the one caution I would offer is that there are just so many experts and analysts around.

"So you can create all kinds of structures -- in the military, we'd say you can create all kinds of spaces -- but there are a limited number of faces with the expertise needed for these spaces," he said.

"So be careful about creating any structures that might really not be necessary if all you are going to end up doing is competing to get the best people from organizations that are doing good work now to fill these new spaces," he said.

The United States accuses Pyongyang of operating a nuclear weapons program based on enriched uranium, violating a 1994 nuclear freeze of its separate plutonium producing program.

Pyongyang has denied running the uranium-based program, but fired up again its once-mothballed plutonium-based program.