North Korea (search) said Thursday it was using plutonium extracted from some 8,000 spent nuclear fuel rods (search) to make atomic bombs, alarming South Korea and other Asian countries that feared the assertion would jeopardize efforts to resolve the nuclear dispute peacefully.

It was unclear whether the announcement was a sign North Korea has turned its back on the possibility of giving up its nuclear capabilities, or was an attempt to gain leverage ahead of any talks on the matter. The North has made similar provocative statements since the nuclear crisis started a year ago, but has engaged in two rounds of talks involving U.S. officials in Beijing (search) since then.

"The [North] successfully finished the reprocessing of some 8,000 spent fuel rods," an unidentified spokesman from the communist nation's Foreign Ministry said in the statement carried by its official news agency, KCNA.

Later Thursday, the top U.N. envoy to the region met with a top North Korean diplomat and said North Korea is still committed to abandoning its nuclear weapons program if the United States promises not to attack.

Maurice Strong met with Vice Foreign Minister Choe Su Hon for about 30 minutes at the United Nations.

"He made it very clear that his government is committed to abandoning its nuclear weapons program, to subjecting itself to internationally agreed inspections and verification procedures, and that their primary concern is their security," Strong said.

Strong said, however, that Choe reiterated North Korea's stance that the United States' "hostile" posture means the North will continue with its nuclear program.

The North Koreans believe that is "the only way that they can try to ensure their own security in the absence of a viable commitment by the United States that it does not intend to attack them," he said.

American intelligence analysts believe North Korea already has at least one or two nuclear bombs. When reprocessed with chemicals, 8,000 rods can yield enough plutonium to make five or six more, according to experts.

North Korea may have reprocessed some rods after U.N. inspectors left the country in January, U.S. officials believe, but how much is unclear. The number is believed to be well under 8,000, however. American officials say reprocessing stopped a few weeks ago and has not restarted.

White House spokesman Scott McClellan said Thursday the United States had not confirmed the North Korean claim, adding, "They've made that statement before."

"There's no legitimate use for plutonium harvested during these procedures," McClellan said. "It would be a clear indication that they are intent on enlarging their nuclear arsenal, despite the call from the international community for North Korea to change its behavior."

In its statement Thursday, North Korea accused the United States of a "hostile policy" toward the country and said it had "made a switchover in the use of plutonium churned out by reprocessing spent fuel rods in the direction [of] increasing its nuclear deterrent force."

Thursday marked the first North Korea said the plutonium from spent rods was used to make nuclear weapons.

The North's statement "could hurt efforts to resolve the nuclear problem peacefully" and "damage the atmosphere of dialogue," South Korean Foreign Ministry spokesman Shin Bong-kil said.

Japan and China did not comment, but other Asian governments -- including Indonesia and the Philippines -- said they also were concerned.

The existence of more than one weapon could mean the isolated regime might part with one bomb, either in a test or by selling it, although a senior official and the main communist newspaper, Rodong Sinmun, said North Korea has pledged not to export its nuclear capability.

Choe, the North Korean vice foreign minister, said the North is expanding its "nuclear deterrence" but would not say how many weapons it has, China's official Xinhua News Agency reported Thursday.

"We [have] no intention of transferring any means of that nuclear deterrence to other countries," Choe was quoted as telling reporters in New York early in the day.

He did not speak with reporters after his meeting with Strong.

North Korea also said Thursday that when necessary, it will reprocess more spent fuel rods from the small reactor in its main nuclear complex in Yongbyon, 50 miles north of Pyongyang.

North Korea restarted its frozen 5-megawatt reactor at Yongbyon after kicking out U.N. nuclear inspectors and quitting the Nuclear Nonproliferation Treaty in January. Experts say it would take a year of operation before the reactor could produce enough to make a new weapon.

Pyongyang tends to escalate its harsh rhetoric in attempts, analysts say, at extracting concessions in crucial negotiations.

Last month, several U.S. government officials told The Associated Press that intelligence analysts are debating the extent of North Korea's nuclear capability.

Among the issues is whether the North has refined its nuclear weapon designs so it can use less plutonium to make a working weapon. Some analysts presume the North Koreans have made advances and thus are able to use their existing stockpile of weapons-grade plutonium more efficiently, the American officials said.

The nuclear dispute flared last October when U.S. officials said North Korea admitted running a secret nuclear weapons program in violation of international agreements.