Washington's No. 2 diplomat said the U.S. is open to dialogue with North Korea if it helps get international nuclear disarmament talks started again, and urged the regime Wednesday to take advantage of the opportunity.

North Korea has been insisting on one-on-one talks with the U.S. after quitting broader six-nation talks on its nuclear program in April. Washington, which had demanded that the North first return to the talks, is now considering direct talks to push disarmament discussions forward.

"There's a tremendous opportunity now for them to take a constructive measure," Deputy Secretary of State James Steinberg told reporters in Seoul after meeting with South Korean officials. "They've certainly given some indication that they understand the value of re-engagement, and we would like to see them take advantage of that."

Pyongyang's official Korean Central News Agency stressed Wednesday that the nuclear dispute is strictly a matter between the North and the U.S., rejecting as "rubbish" and "ridiculous" South Korean President Lee Myung-bak's recent proposal aimed at resolving the dispute.

North Korea has long claimed that what it calls the U.S. "hostile policy" and nuclear threats against the regime forced it to develop atomic bombs.

Pyongyang's Foreign Ministry later said the North wants a nuclear-free Korean peninsula, but its denuclearization efforts will be made "in relation to the U.S. policy" toward it. The ministry said it is "unthinkable even in dreams" to abandon nuclear weapons as long as there remain the "root causes that pushed us to possess nuclear weapons."

The ministry also rejected a recent U.N. Security Council resolution adopted at last week's U.N. nuclear summit to call for a nuclear-free world. The resolution was aimed, in part, at the widely denounced nuclear programs of Iran and North Korea, although they were not named.

Steinberg reiterated Washington's position that it is prepared for direct engagement with North Korea if it helps to resume the six-party talks involving the two Koreas, the U.S., China, Russia and Japan. He said North Korea should make clear that Pyongyang also is "prepared to engage on those terms."

Steinberg's visit comes days before Chinese Premier Wen Jiabao is to travel to Pyongyang. China, North Korea's biggest source of economic aid and diplomatic support, could be key in pushing for the resumption of the six-nation talks.

Pyongyang could announce some concrete disarmament measures during Wen's Oct. 4-6 trip, while China may promise food and fuel aid in return, South Korea's Yonhap news agency said in a report earlier this week, citing unidentified diplomatic sources in Beijing.

North Korean leader Kim Jong Il reportedly expressed a willingness to engage in "bilateral and multilateral talks" during a Sept. 18 meeting with Chinese presidential envoy Dai Bingguo. That appeared to indicate the country would reconsider returning to the six-party negotiations.

The country also has made a series of conciliatory gestures toward Seoul and Washington in recent months, including releasing Americans and South Koreans in its custody.

Steinberg said the U.S. supports South Korea's latest proposal, which would give the North economic and political incentives, including a security guarantee, in exchange for the regime irreversibly dismantling its nuclear program in one step, instead of in phases. Lee proposed the so-called "grand bargain" during his trip to New York last week.

KCNA rejected the proposal, accusing Lee of seeking to "meddle and stand in the way of settling the nuclear issue between" the North and the U.S.

Earlier Wednesday, Lee told a news conference he believes North Korea would not reject his proposal as it would also deal with the North's demand that the U.S. abandon what Pyongyang calls its "hostile policy."

Steinberg, on an Asian tour that also included stops in Vietnam, Malaysia and China, travels to Japan later Wednesday.