Secretary of State Colin Powell Monday rejected suggestions the United States is being inflexible in its approach to the six-party talks on North Korea's nuclear program, which have resumed in Beijing. Mr. Powell discussed the issue with the director-general of the International Atomic Energy Agency, Mohamed el-Baradei.

The negotiations in Beijing resumed at the working-group level Monday amid news reports of frustration among some participants, notably South Korea, about what they consider an uncompromising approach by the Bush administration.

But in a talk with reporters after this meeting with Mr. el-Baradei, Secretary Powell insisted the United States is approaching the six-party talks with a "spirit of flexibility" while at the same time holding to its position that the process should result in the verifiable dismantling of the North Korean nuclear program.

At the last round of Chinese-hosted talks, North Korea offered to freeze its nuclear program in return for aid from other parties to the talks.

Under questioning here, Mr. Powell reiterated the long-standing U.S. refusal to reward Pyongyang for returning to the nuclear freeze it ostensibly promised in a 1994 agreement with the United States.

But he also made clear the United States would not stand in the way of other parties in the talks who might decide to extend aid to North Korea before a final disarmament deal is struck:

"The other members of the six-party talks have indicated a willingness to provide some assistance rather quickly," said Mr. Powell. "The United States will want to see performance on the part of the North Koreans. But we will enter these talks as we have entered previous talks, with flexibility and with an attitude of trying to solve this problem, not for the purpose of continuing the problem and not finding a solution."

The Bush administration has said it would be prepared to join in multilateral guarantees for North Korea's security but only after North Korea has pledged to irreversibly dismantle its nuclear program.

It has also said that following such an agreement, it might revive the so-called "bold approach" of increased aid and recognition for North Korea that it was considering before the nuclear crisis erupted in 2002.

For his part, Mr. el-Baradei told reporters he considers the North Korean nuclear issue "one of the most dangerous challenges facing the international community."

The International Atomic Energy Agency chief said hopes the IAEA, which was expelled from North Korea at the end of 2002, will "soon be in a position" to go back and return that country's nuclear facilities to international supervision.

The six-party talks include the United States, North and South Korea, host China, along with Japan and Russia. The working-group meetings are expected to give way to higher-level plenary talks later this week.