"By passing such a resolution, we will send a clear message to the North Korean regime that its actions will not be tolerated," Mr. Bush said Saturday in his weekly radio address.
Uncertainty remains about whether North Korea actually detonated a nuclear device. So far, no trace of radioactive material has been found in air samplings conducted by the United States, China and Japan.
Either way, Mr. Bush called the underground explosion a threat to international peace and stability. He is dispatching Secretary of State Condoleezza Rice to China, South Korea and Japan next week to assess the security situation in the region.
"With its actions this week, the North Korean regime has once again broken its word, provoked an international crisis and denied its people the opportunity for a better life," Mr. Bush said. "We are working for a resolution to this crisis."
Critics of Mr. Bush's foreign policy say the apparent nuclear test is evidence that the administration's approach to North Korea has failed. Democrats say that since Mr. Bush became president, both North Korea and Iran have bolstered their nuclear weapons capabilities.
"Under President Bush and this Republican Congress' watch, our country has become less safe — both domestically and abroad," said congressional candidate Patrick Murphy of Pennsylvania. "We have seen the number of terrorist attacks increase around the world. We have seen North Korea and Iran — two members of the president's axis of evil — enhance their nuclear weapons capabilities."
Delivering the Democrats' weekly radio address, Murphy also criticized the president for his policy regarding Iraq.
"I have seen firsthand the right and wrong way to engage in war, and it is clear that President Bush and this Republican Congress have it wrong," said Murphy, a veteran of the Iraq war. "In Baghdad in 2003 I ran conveys up and down Ambush Alley in a Humvee without doors. Nineteen men in my unit never returned home. ... My fellow soldiers continue to die in Iraq without a clear mission, without benchmarks to determine success and without a clear timeline for coming home."
On North Korea, the U.N. Security Council will vote Saturday on a resolution that would impose nonmilitary sanctions on the repressive regime. The latest draft says any further action the council might want to take would require a new resolution.
The resolution also eliminates a blanket arms embargo, instead targeting specific equipment for sanctions, including missiles, tanks, warships and combat aircraft. The draft prevents the sale or transfer of luxury goods and material and technology that could contribute to North Korea's nuclear, ballistic missile or other weapons of mass destruction-related programs.
It would also freeze the financial assets of individuals and entities with any connection to North Korea's weapons or missile programs as well as a travel ban on those associated with the programs.
In admonishing North Korea's purported nuclear test, Mr. Bush has accused Pyongyang of being one of the world's leading proliferators of missile technology, including transfers to Iran and Syria.
According to U.S. officials and outside experts, Pyongyang has sold military goods to at least 18 countries, mostly in Africa and the Middle East. But North Korea's customer list, going back to the mid-1980s, is said to go well beyond Iran and Syria. U.S. officials, recent public assessments and outside experts report sales of missiles or related components to Egypt, Iran, Pakistan, Libya, Syria, the United Arab Emirates and Yemen.