SEOUL, South Korea - North Korea on Tuesday blasted U.N. sanctions aimed at punishing the country for its nuclear test, saying the measures amount to a declaration of war and that the nation wouldn't cave in to such pressure now that it's a nuclear weapons power.
The bellicose remarks - the central government's first response to the U.N. measures imposed last weekend - came as China warned the North against stoking tensions and the American nuclear envoy arrived in South Korea for talks.
The North broke two days of silence about the U.N. resolution adopted after its Oct. 9 nuclear test, issuing a Foreign Ministry statement on its official Korean Central News Agency.
"The resolution cannot be construed otherwise than a declaration of a war" against the North, also known as the Democratic People's Republic of Korea.
The North warned it "wants peace but is not afraid of war" and that it would "deal merciless blows" against anyone who violates its sovereignty.
The communist nation "had remained unfazed in any storm and stress in the past when it had no nuclear weapons," the statement said. "It is quite nonsensical to expect the DPRK to yield to the pressure and threat of someone at this time when it has become a nuclear weapons state."
China has long been one of North Korea's few friends, but relations have been frayed in recent months by Pyongyang's missile tests and last week's nuclear blast.
On Tuesday, Chinese Foreign Ministry spokesman Liu Jianchao warned Pyongyang against aggravating tensions and said the North should help resolve the situation "through dialogue and consultation."
The verbal volley came as the U.S. pressed on with a round of diplomacy in Asia aimed at finding consensus on how to implement the sanctions. Secretary of State Condoleezza Rice was expected to arrive in Japan on Wednesday before traveling to South Korea and China.
After landing in Seoul on Tuesday, the U.S. nuclear envoy, Assistant Secretary of State Christopher Hill, said he couldn't confirm media reports that the North may be preparing for another test explosion.
But Hill stressed that the international community should make the North pay a "high price" for its "reckless behavior."
Hill told reporters he wanted to talk to South Korean officials about reports the North was getting ready for a second nuclear test. Japan's government also had "information" about another possible blast, Foreign Minister Taro Aso told reporters, without elaborating.
But a senior South Korean official told foreign journalists that despite signs of a possible second test, it was unlikely to happen immediately.
"We have yet to confirm any imminent signs of a second nuclear test," the official said on condition of anonymity because of the sensitivity of the information.
China, whose support for the sanctions is key to whether they will have any impact on neighboring North Korea, began examining trucks at the North Korean border.
The measures ban trade with the North in major weapons and materials that could be used in its ballistic missile and weapons of mass destruction programs. They call for all countries to inspect cargo to and from North Korea to enforce the prohibition.
Hill planned to meet his South Korean counterpart, Chun Yung-woo, and the two were to hold a three-way meeting with their Russian counterpart, Deputy Foreign Minister Alexander Alexeyev, who has been in Seoul since Sunday.
Russian Prime Minister Mikhail Fradkov was also due in Seoul for talks with his South Korean counterpart. North Korea was expected to top their agenda.
South Korea has said it would fully comply with the sanctions but has also indicated that it has no intention of halting key economic projects with the North, despite concerns that they may help fund the North's nuclear and missile programs.
"Sanctions against North Korea should be done in a way that draws North Korea to the dialogue table," South Korean Prime Minister Han Myung-sook said Tuesday ahead of her meeting with Fradkov, according to Yonhap news agency. "There should never be a way that causes armed clashes."
In Washington, U.S. National Intelligence Director John Negroponte's office said Monday that air samples gathered last week contain radioactive materials that confirm that North Korea conducted an underground nuclear explosion.
In a short statement posted on its Web site, Negroponte's office also confirmed that the size of the explosion was less than 1 kiloton, a comparatively small nuclear detonation. Each kiloton is equal to the force produced by 1,000 tons of TNT.
It was the first official confirmation from the United States that a nuclear detonation took place, as Pyongyang has claimed.
Meanwhile, the U.S. envoy on North Korean human rights, Jay Lefkowitz, urged China and South Korea to rethink aid policies to North Korea, saying unmonitored assistance could prop up a "criminal regime."
China and South Korea provide large amounts of badly needed economic and energy aid. Both Beijing and Seoul worry that a collapsed regime in Pyongyang could send refugees flooding over their borders.