WASHINGTON (AFP) - US President George W. Bush said he was confident the alliance confronting North Korea"s nuclear policy will enforce UN sanctions against Pyongyang, despite South Korea"s refusal to cut off key economic projects in the north.

"The coalition remains firm, and we will continue to work to see to it that it does remain firm," Bush told a White House news conference, referring to the five-nation group that is trying to press North Korea back into disarmament negotiations.

The president said US Secretary of State Condoleezza Rice had briefed him on her tour last week of Washington"s partners in the coalition --- China, Japan, Russia and South Korea -- and that all four governments pledged to back the sanctions.

"All countries understand we must work closely together to solve this problem peacefully," Bush said during the press conference, which focused primarily on the conflict in Iraq.

The UN Security Council unanimously adopted the sanctions after North Korea carried out its first nuclear test explosion on October 9.

The sanctions include a ban on trade in weapons-related material, financial measures to prevent the funding of Pyongyang"s military and the search and seizure of cargo to and from North Korea suspected of containing banned weapons.

Rice reported strong support for the sanctions from all four countries, and particularly China, North Korea"s long-time benefactor and main source of trade and aid.

But the South Korean government reaffirmed Wednesday that it would not close two major investment projects in the North which critics assert funnel money indirectly to Pyongyang"s military programs.

The initiatives -- an industrial park in North Korea"s Kaesong and tours to the scenic Mount Kumgang tourist area -- were launched under Seoul"s so-called "sunshine policy" of engaging the north in hopes of lessening its isolation.

South Korea said it was drawing up a report for the United Nations on measures it will take under the North Korea sanctions resolution.

But Vice Foreign Minister Lee Kyu-Hyung said Kaesong and Mount Kumgang "have nothing to do with the UN Security Council resolution".

Bush also brushed aside bellicose rhetoric from North Korean leader Kim Jong-Il, who has threatened to retaliate against the United States and neighboring states which join in imposing sanctions.

"The leader of North Korea likes to threaten," he said.

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