U.S. President George Bush says North Korea is once again testing the resolve of nations trying to stop its nuclear weapons program.

President Bush says it is not the first time North Korean leader Kim Jung Il has threatened reprisals against those opposed to its nuclear program.

"The leader of North Korea likes to threaten," he said. "In my judgment, what he is doing is testing the will of the five countries that are working together to convince him there is a better way forward for his people."

The United States, China, Russia, Japan, and South Korea say they will enforce U.N. Security Council sanctions against North Korea that followed Pyongyang's first nuclear test October 9.

Those sanctions include a ban on North Korea trading weapons-related materials as well as financial restrictions meant to prohibit its development of more weapons.

During a White House news conference, President Bush said he has been briefed on the situation by U.S. Secretary of State Condoleezza Rice, who just returned from the region.

Mr. Bush says Rice told him that China, South Korea, Japan and Russia are united behind the sanctions.

"Our goal is to continue to remind our partners that when we work together, we are more likely to be able to achieve the objective, which is to solve this problem diplomatically," he said. "So I would report to you that the coalition remains firm."

North Korean officials say South Korea will pay, what they call, "a high price" for backing international sanctions against Pyongyang. North Korea says it considers U.N. sanctions an act of war.

South Korea says it supports the sanctions, but will continue to pursue some economic cooperation with the North meant to encourage eventual reunification.