North Korean leader Kim Jong Il (search) rebuffed a U.S. demand for immediate disarmament talks to end his nuclear weapons programs, saying Washington needs to show sincerity and meet his conditions, his country's official news agency said Tuesday.

But in a rare comment on the nuclear standoff, the reclusive Stalinist leader also said his government's commitment to a peaceful solution to the nuclear dispute remains unchanged, raising hopes that Kim would eventually go for a deal.

Both China and South Korea urged the United States and North Korea (search) on Tuesday for more flexibility in the two-year-old confrontation.

"We will go to the negotiating table anytime if there are mature conditions for the six-party talks thanks to the concerted efforts of the parties concerned in the future," Kim told a visiting Chinese envoy, expressing the hope that the United States would show "trustworthy sincerity," according to the Korean Central News Agency.

Kim's comments came less than two weeks after he flouted Washington and its allies by claiming that it had nuclear weapons and would boycott the talks.

Kim spoke of his government's new position on Monday in a meeting with Wang Jiarui, head of the Chinese Communist Party's International Department, KCNA said.

He also said North Korea "would as ever stand for the denuclearization of the Korean Peninsula and its position to seek a peaceful solution to the issue through dialogue remains unchanged," the agency reported.

KCNA did not elaborate on what conditions Kim cited to the envoy from China, his impoverished country's only remaining major ally.

In Washington, State Department spokesman Lou Fintor said the United States will "resume the six-party talks at an early date without preconditions."

Japan's Chief Cabinet Spokesman Hiroyuki Hosoda urged North Korea to return to negotiations "unconditionally."

After Wang's delegation returned to Beijing from Pyongyang, Chinese Foreign Ministry spokesman Kong Quan said the nuclear standoff was at a "crucial juncture" and urged both the United States and North Korea to demonstrate more "sincerity and flexibility."

Kong wouldn't say whether China had offered North Korea more aid to return to talks.

But Russia's ITAR-Tass news agency, quoting a source close to the Chinese Embassy in Pyongyang, reported that Wang told Kim that China was ready to increase oil deliveries to North Korea if it returned to the six-nation talks.

Following Pyongyang's rejection of further meetings over the nuclear issue on Feb. 10, China drastically decreased oil deliveries to the energy-starved North, the report said.

"This is not the sole lever of pressure on Pyongyang that Beijing has," ITAR-Tass quoted its unidentified source as saying.

Beijing has repeatedly called for "patience and calm" from all involved parties, and has said it did not believe sanctions would work against North Korea.

South Korea's Unification Minister Chung Dong-young called for a similar approach, citing what he called "two minimum conditions" that needed to be met before the talks could resume.

"The United States should recognize North Korea as a negotiation partner," Chung told South Korea's MBC Radio, without elaborating. "North Korea in its part should withdraws its conditions for coming to the negotiating table."

In its rejection of further meetings over the nuclear issue on Feb. 10, North Korea said it would only return to the talks that include South Korea, China, Russia and Japan if the United States drops what Pyongyang called a "hostile" policy toward the North.

At that time, it condemned a statement by Secretary of State Condoleezza Rice who called North Korea an "outpost of tyranny," saying it was evidence that Washington is seeking a regime change in Pyongyang.

During three rounds of talks in Beijing since 2003, North Korea has demanded more aid and a peace treaty with Washington in exchange for giving up its nuclear program — measures that it apparently hopes will guarantee the survival of Kim's regime.

The talks have made little progress amid deep distrust between Washington and Pyongyang. The United States wants a verifiable nuclear freeze and weapons dismantlement as part of any deal. North Korea says it remains convinced Washington wants to topple its communist regime, and that it needs a nuclear deterrent for protection.

Though China helped defend North Korea in the 1950-53 Korean War, Beijing worries that a nuclear-armed North would raise tensions in the region and prompt Japan and South Korea to develop atomic weapons.