Though the White House softened its tone on North Korea by hinting that a sweeter energy and food deal may be had in exchange for disarmament, Pyongyang hasn't let up on its militaristic tone toward Washington.

The communist country warned through state-run Korean Central News Agency that "the U.S. imperialist aggressors had better properly judge their rival and stop acting rashly."

Also on Tuesday, Pyongyang said it was running out of patience with Washington and threatened to exercise undefined "options."

The vaguely worded statement issued by Pyongyang did not specify what options it was considering, but suggested the isolationist nation was prepared to escalate the crisis over its drive to develop nuclear weapons.

North Korea has yet to directly respond to President Bush's assurances that the United States seeks to help, not obliterate, the country, nor has it answered China's offer to host talks between Washington and Pyongyang — where the prospect that Washington will drop its most lethal sticks and lay out some tasty carrots is increasingly likely.

President Bush also didn't have a response on Tuesday to China's offer, but did say that nations in the region should "bind together" and tell the North Koreans "we expect them to disarm — we expect them not to develop nuclear weapons." If the North does so, then Washington would consider new talks about food and energy aid to the impoverished nation.

U.S. Assistant Secretary of State James Kelly, who arrived in China from Seoul on Tuesday night for meetings on North Korea and its nuclear-weapons program, said Wednesday morning he was "very reassured" at how his talks with Asian nations about the issue are unfolding.

On Wednesday, the U.S. military said North Korean soldiers have stepped up patrols in one area of the Demilitarized Zone separating the two Koreas.

"Over the past week, we have some increased activity," said Lt. Col. Matthew Margotta, who commands a combined battalion of U.S. and South Korean soldiers stationed near the border village of Panmunjom. He described the activity as "not alarming, just unusual."

In Seoul, Kelly reassured South Korean officials that Washington would stick to diplomacy to seek a peaceful settlement to the crisis. He also held out the prospect of energy assistance to the North if it verifiably gives up its nuclear ambitions. North Korea suffers an acute energy shortage.

"I had excellent meetings in (South) Korea," Kelly said, leaving his hotel for the Chinese Foreign Ministry on Wednesday morning. "I'm very reassured. We have to keep talking with each other to make sure that things are done in the best possible way."

In a statement Tuesday, however, North Korea accused Washington of being insincere about prospects for dialogue. It insisted it was not moving to reactivate its nuclear facilities in order to wrest concessions out of the West.

The North defended its decision last week to withdraw from a global nuclear non-proliferation treaty and said in a second statement Tuesday that there was a limit to its "self control" in the face of what it calls U.S. aggression.

If the United States responds to the withdrawal from the treaty "with new sanctions, blockade and pressure offensives, (North Korea) will exercise the second and third corresponding options," a commentary in Rodong Sinmun, North Korea's most prominent state newspaper, said.

Possible further next steps for the North would include suspending its moratorium on missile tests — as it has threatened — or go ahead with a test. A more extreme option would be to begin developing weapons-grade plutonium at a reprocessing plant that they say is ready for operation.

The commentary, carried by the North's news agency, said the withdrawal from the nonproliferation treaty had been a "legitimate option" and was "guaranteed by its powerful military capacity."

Meanwhile, White House press secretary Ari Fleischer denied a report by Japan's Kyodo News agency that the United States has proposed providing North Korea with a written security guarantee signed by Bush.

"There is no truth to it," Fleischer said.

In a push for diplomacy, the Chinese Foreign Ministry said it would be willing to negotiate talks in Beijing between the United States and China's communist ally.

Beijing's dual position — as a powerful member of the U.N. Security Council and one of North Korea's few allies — would give it a unique perspective on the issue.

Secretary of State Colin Powell said that if North Korea agrees to abandon its nuclear ambitions, the United States would want to enter a "a new arrangement" — stronger than a 1994 deal — to better constrain Pyongyang's ability to produce nuclear weapons.

Under the 1994 agreement, the North agreed to abandon all weapons activities in return for U.S. and international aid to build two light-water nuclear reactors for energy production.

The 1994 agreement "left intact the capacity for production. I think, therefore, that we need a new arrangement and not just go back to the existing framework," Powell told The Wall Street Journal in an interview published in its Tuesday editions.

North Korea has protested the suspension of U.S. fuel shipments following its admission last fall of a secret nuclear weapons program. The North says it will resolve U.S. security concerns if Washington signs a nonaggression pact.

Many see the steps as a ploy by a desperately poor and isolated nation to trade its nuclear programs for much-needed assistance and diplomatic ties. On Monday, White House spokesman Ari Fleischer accused North Korea of attempting blackmail.

But the North's news agency report Tuesday said recent moves were prompted by Washington's aggressive attitude. While denying that Pyongyang posed a threat to the world, the report said the country was ready to fight military moves against it.

The denial of brinkmanship came a day after Kelly suggested the possibility of American energy aid. On Tuesday, Kelly met President Kim Dae-jung's two top security advisers.

"Both sides reaffirmed that they should respond calmly and discreetly to North Korean actions under the principle of resolving the problem peacefully and diplomatically," the presidential office said.

The two sides also agreed to seek cooperation from Russia, China and the U.N. International Atomic Energy Agency for an "early and peaceful" resolution to the standoff, the news release said.

Pyongyang appeared to dismiss such efforts, though analysts regards its harsh rhetoric as an attempt to push Washington into talks.

On North Korea's drive to develop nuclear weapons, U.N. Secretary-General Kofi Annan said "very intensive efforts" were under way in Washington, Moscow, Beijing, Seoul and Tokyo to resolve the crisis. "I think this is the right way to go," he said.

"I think the signals coming from both the U.S. and Korea gives me hope and encouragement that it will be possible with determined effort to find a diplomatic solution," he said.

International efforts to defuse the confrontation widened Tuesday when envoys from the United Nations and Australia headed to North Korea.

In addition, Russia said Tuesday that Deputy Foreign Minister Alexander Losyukov will travel to China, North Korea and the United States.

The Associated Press contributed to this report.