U.S. Secretary of State Colin Powell says Washington is approaching talks on North Korea's nuclear program with a spirit of flexibility. But he also reiterated the long standing U.S. demand that the communist government prove it will stop developing nuclear weapons.

Powell said Tuesday that the U.S. will enter the nuclear negotiations as it has entered into previous rounds of talks - with flexibility and with an attitude of trying to resolve the problem.

Powell made the remarks in a news conference Monday after meeting with Mohamed ElBaradei, director general of the International Atomic Energy Agency in Washington.