The United States says it is not ready to engage broadly with North Korea, despite recent warmer relations.
Secretary of State Condoleezza Rice said the North Koreans must first abandon all elements of their nuclear weapons programme.
President Bush previously referred to North Korea as part of an axis of evil.
But last week, he wrote a personal letter to North Korean leader Kim Jong-il and this week a US orchestra got permission to play in Pyongyang.
Ms Rice's comments come despite positive remarks by her deputy after a visit to Pyongyang, the BBC's Rajesh Mirchandani notes.
Assistant Secretary of State Christopher Hill had said he was hopeful North Korea would provide a full declaration of its nuclear programmes by around the end of the year.
This is broadly in line with the country's promise to reveal and stop all its nuclear activities in exchange for fuel and economic aid.
Even though Condoleezza Rice said she was pleased about news the New York Philharmonic Orchestra was being allowed to play in North Korea, she insisted denuclearisation was the priority and that North Korea was "not a regime the United States is prepared to engage broadly". ( BBC )