In a news conference outside the White House Wednesday Mr. Bush said the United States is working to confirm Pyongyang's claim. He said the claim itself is a threat to international peace and stability.
He said the United States agrees with other countries that there must be a strong U.N. Security Council resolution that will require North Korea to abide by its commitment to dismantle its nuclear programs.
But Mr. Bush said the United States has no intention of attacking North Korea.
Also during the Rose Garden news conference, President Bush blamed sectarian militants for a recent upturn in violence in Iraq during the Ramadan holy season.
He vowed that the United States will stand with the young Iraqi government. And he said it is in the U.S. interests that Iraq succeed.
Mr. Bush also offered his "heartfelt condolences" for those who have suffered from attacks in Iraq.