Secretary of State Colin Powell said Monday he has received assurances from Pakistani President Pervez Musharraf that "there are no further contacts" between Pakistan and North Korea concerning transfers of nuclear weapons technology to Pyongyang.

Powell, speaking to reporters while en route here from Washington, commented in response to news reports over the past several weeks of secret Pakistani cooperation with North Korea in Pyongyang's development of uranium-based nuclear weapons.

Powell was careful to use the present tense in his response, leaving open the possibility that the such cooperation existed in the past. The New York Times on Sunday quoted officials as saying the technology transfers were being made as recently as last July.

"I have made it clear to him [Musharraf] that any sort of contact between Pakistan and North Korea we believe would be improper, inappropriate and would have consequences," Powell said.

He noted that laws require U.S. sanctions against countries that engage in weapons proliferation.

"We will obey the law," he said, adding that nothing has been reported to him presently that requires follow-up action. He said he is not aware of any administration examination of past Pakistani activities in this regard.

The Bush administration regards Pakistan as a key ally in the war on terrorism. Any corroboration of the Pakistani-North Korea nuclear cooperation relationship would be a major setback to U.S. ties with Pakistan because the United States would be forced under law to cut back on most assistance programs.

Under such circumstances, the probable result would be diminished Pakistani cooperation in the war on terrorism.

Administration officials have repeatedly praised Musharraf for his willingness to confront Islamic extremism within Pakistan and to oppose terrorism wherever it occurs.