Nations with a direct stake in North Korea's nuclear arms capacity need to unite in facing down its threat, President Bush said Thursday, because direct talks have failed.

Bush was answering critics who say his refusal to negotiate directly with Pyongyang is the wrong approach to the burgeoning crisis.

"We've tried bilateral negotiations," Bush said, referring to an aid-for-disarmament deal negotiated by the Clinton administration. "The United States honored its side of the agreement, North Korea didn't."

Bush's prime-time news conference in the White House's East Room was principally concerned with Iraq, but took time to address the North Korean crisis.

He ticked off the list of neighboring countries which he says "have got a direct stake in whether North Korea has nuclear weapons:" China, South Korea, Japan and Russia.

He suggested that a coordinated effort to isolate Kim Jong Il's Stalinist regime was the likeliest way to stand it down.

Those nations "must stand up to their responsibility, along with the United States, to convince Kim Jong Il that the development of a nuclear arsenal is not in his nation's interests, and that should he want help in easing the suffering of the North Korean people, the best way to achieve that help is to not proceed forward," Bush said.

He did not provide details, but the Bush administration wants to ensure that other nations do not provide North Korea with the massive economic assistance it has demanded from the United States.

The standoff over North Korea's suspected efforts to develop nuclear weapons has escalated in recent weeks, with Pyongyang engaging in increasingly bold military maneuvers.

Last month, North Korean MiG fighters intercepted a U.S. surveillance plane in international airspace off North Korea's coast. The United States has responded by ordering heavy bombers to Guam.

The Bush administration says it will not be bullied into giving North Korea the nonaggression treaty and economic aid it demands.

Bush has said he seeks a diplomatic solution to the nuclear dilemma, but has not ruled out a military option. Washington has insisted North Korea "visibly verifiably and irreversibly" dismantle its nuclear weapons program.

Democrats say direct talks offer the only chance of defusing the nuclear crisis.

Russia and China also both urged Washington to hold direct talks with Pyongyang, saying they opposed military or other pressure on the isolated country.

After Bush's comments, South Korea's Foreign Ministry had no comment.

Tensions emerged in October, when the United States said North Korea, believed to already have one or two plutonium bombs, admitted having the capacity to enrich uranium for nuclear weapons.

North Korea then ejected United Nations nuclear monitors, withdrew from the Nuclear Nonproliferation Treaty and, last week, restarted a nuclear reactor that U.S. officials say was designed to produce plutonium for nuclear weapons. Pyongyang says the reactor is to generate electricity.

The administration is also concerned that the North will restart a nuclear reprocessing facility plant, also at the Yongbyon nuclear complex, that extracts weapons-grade plutonium from spent fuel rods and could enable the production of bombs within months.