One day after U.S. officials held out the prospect of food and energy supplies, Pyongyang declared it would not accept any offer of dialogue with conditions attached.

Washington's "loudmouthed supply of energy and food aid are like a pie in the sky, as they are possible only after the DPRK is totally disarmed," a North Korean Foreign Ministry spokesman said, according to the official news agency KCNA. 

Spokesman Ari Fleischer said Wednesday the White House had heard no official word from Pyongyang. 

"That's an additional unfortunate comment that North Korea has made," he said of the North's reported dismissal of a possible aid deal. 

The United States has been seeking a diplomatic solution to the nuclear crisis, and in a further step toward a peaceful settlement, North and South Korea on Wednesday set dates for Cabinet-level talks Jan 21-24. 

U.S. envoy James Kelly, before meetings in Beijing on the North Korean stalemate, said he was "reassured" by efforts to persuade the North to give up its nuclear weapons development. 

Kelly earlier this week had extended one of Washington's tentative aid offers. And China has offered to host negotiations between the United States and North Korea. 

Still, there were signs the North has increased military patrols near its border with the South, and the reclusive regime in Pyongyang kept up its stream of anti-American invective through its state-run media. 

In addition to rejecting the possibility of aid, the North also blamed nuclear proliferation on the United States and accusing Washington of using its weapons to threaten and blackmail other nations. 

Tensions on the Korean peninsula have been rising since North Korea admitted in October to having a secret nuclear program. Last week the communist regime withdrew from a global treaty aimed at limiting the spread of nuclear weapons, and threatened to resume missile tests. 

The U.S. military spotted increased patrols by North Korean soldiers over the past week in part of the Demilitarized Zone dividing the peninsula, said Lt. Col. Matthew Margotta, who commands a combined battalion of U.S. and South Korean soldiers. 

But the activity in the 2 1/2-mile-wide, 156-mile-long DMZ were "not alarming, just unusual," and were probably "triggered by a heightening of tensions," Margotta said. 

The North Koreans have also occupied a guard tower in the DMZ that hadn't been used in years, he said. 

In a speech Wednesday at the Yongsan command headquarters for U.S. troops in South Korea, President-elect Roh Moo-hyun called the U.S.-South Korean alliance the "driving force" for security in the region. 

"We can never accept North Korea's nuclear weapons program," Roh said, calling for international diplomacy to defuse the standoff. "The South Korean-U.S. alliance should be the basis for this effort." 

The United States keeps 37,000 troops in South Korea, and the accidental killing of two teenage girls by American soldiers driving a military vehicle had increased calls that the force be scaled down. 

The North has continually tried to drive a wedge between the South and the United States, its key ally, and on Wednesday called for a joint Korean struggle against "U.S. imperialists." 

"If the North and South join forces and take a joint stand, we can protect the nation's dignity and safety against U.S. arrogance," said Pyongyang Radio, monitored by South Korea's national Yonhap news agency. 

Also Wednesday, the head of the International Atomic Energy Agency, Mohamed ElBaradei, urged Russia to get involved in diplomatic efforts, saying Moscow could play a "vitally important role." 

Throughout the conflict, the North has maintained its insistence that the United States sign a nonaggression treaty in exchange for dialogue - a condition it repeated Wednesday. 

"It is clear that the U.S. talk about dialogue is nothing but a deceptive drama to mislead the world public opinion," the news agency report said, quoting an unidentified foreign ministry spokesman. 

He also reportedly said the stalemate could be resolved only when both sides negotiate "on an equal footing through fair negotiations that may clear both sides of their concerns." 

Also Wednesday, the news agency rejected international concern over its nuclear programs and blamed nuclear proliferation on the United States. 

"In 1945, the U.S. produced three A-bombs and tested one of them in its mainland and dropped the other two on Hiroshima and Nagasaki, inflicting nuclear holocaust on the Japanese for the first time in human history," the dispatch said. 

The report, monitored in Seoul, said the United States and other countries were trying to shift the blame to North Korea, pressuring it to rejoin the Nuclear Nonproliferation Treaty, which says only Britain, China, France, Russia and the United States can have nuclear weapons.