"There are no surprises," said Chun Yung-Woo, Seoul's lead negotiator in stalled six-nation talks on the North's disarmament which the communist regime has boycotted since late last year.
Chun called it "the usual rhetoric that they have been using."
His comments came just before a meeting in Seoul with his Russian and US counterparts as delegates to the talks, Russian Deputy Foreign Minister Alexander Alexeyev and US envoy Christopher Hill.
"I don't think it really contained anything new," Hill said after the meeting, when asked about the North's statement.
"Frankly I don't think it is particularly helpful to anybody, especially not helpful to North Korea."
Hill also commented on Japanese and US media reports that the North may be planning a second test.
"I think we would all regard a second test as a very belligerent answer on North Korea's part to the international community," he said. "I think the international community will respond very clearly to the DPRK (North Korea) on this."
The US envoy said the North must understand "that the international community is not going to accept the DPRK as a nuclear state.
"I think the DPRK is under some impression that once they make a nuclear test, somehow we will respect them more. The fact of the matter is, a nuclear test makes us respect them less."
Hill arrived in the South Korean capital on Tuesday as part of a swing through Asia to shore up enforcement of the sanctions, which were approved unanimously by the UN Security Council on Saturday after the North tested an atomic bomb.
In a foreign ministry statement, North Korea said the UN resolution was a "declaration of war" and warned nations not to follow the United States in trying to implement them.
"We will deliver merciless blows without hesitation to whoever tries to breach our sovereignty and right to survive under the excuse of carrying out the UN Security Council resolution," a ministry spokesman said.

Copyright AFP (Agence France-Presse), 2006