North Korea (search) said Saturday that South Korea's secret nuclear experiments involving uranium and plutonium make the communist state more determined to pursue its own nuclear programs, a news report said.

A spokesman for North Korea's Foreign Ministry condemned the South Korean nuclear experiments, conducted in 1982 and 2000, as "clearly of military nature," according to Pyongyang's official news agency KCNA, monitored by South Korea's national news agency Yonhap.

Officials had feared the recent revelations of those experiments would affect the prospects for six-nation talks aimed at persuading North Korea to abandon its nuclear weapons programs, the unnamed North Korean spokesman was quoted as saying.

"We strongly suspect that the United States may have masterminded the experiments that were clearly of military nature," he was quoted as saying. "We cannot but link these developments with the issue of holding six-party talks."

South Korea said Thursday that it extracted a tiny amount of plutonium, a key element for making atomic bombs, in a nuclear experiment in 1982. That revelation followed an acknowledgment last week that it enriched a small amount of uranium — another element that could be used to make a bomb — in 2000.

The controversy over South Korea's experiments has threatened to further disrupt troubled efforts to persuade North Korea to dismantle its suspected nuclear weapons programs.

"Under these circumstances, it is only natural that we should never give up our nuclear program," the North Korean spokesman said.

The North Korean threat, which follows a pattern of issuing hard-line statements in times of crucial negotiations, came as a delegation of top Chinese government and Communist Party leaders are visiting Pyongyang to discuss issues including the North's nuclear programs.

China, North Korea's key ally, has been host to three rounds of six-nation talks on ending North Korea's nuclear ambitions, but those talks ended without breakthroughs. The talks involve the United States, the two Koreas, China, Japan and Russia.

In a meeting in Tokyo, diplomats from Japan, South Korea and the United States reconfirmed Friday that the next round of six-nation talks must be held later this month as scheduled.

North Korea's reluctance to participate has stalled efforts to restart the talks, while South Korea's recent acknowledgment it had conducted nuclear experiments threatened to further complicate the negotiations.

South Korea denies any nuclear weapons ambitions, calling those experiments purely "scientific research activities." It says it has been cooperating fully with U.N. nuclear inspectors to ensure transparency.

In an interview Friday with The Associated Press, U.S. Secretary of State Colin Powell (search) said Powell attached minimal importance to the recent disclosures that South Korea had engaged in a uranium enrichment experiment four years ago and a plutonium-based nuclear experiment two decades ago.

"It's quite clear that these were not intended other than for academic, experimental purposes, and it's over with and I think that's, frankly, the end of the matter," Powell said.

"I don't see any great significance to them, but the North Koreans always like to seize on anything to make their point."

In its first reaction to the South Korean experiments, however, a North Korean envoy to the United Nations (search) in New York warned Wednesday that the South Korean nuclear activities could trigger a nuclear arms race in Northeast Asia.