The United States has said that Pakistan President Pervez Musharraf is 'aggressively moving' to probe claims that Pakistan was the source of the centrifuge design technology in Libya's nuclear programme.

"I am pleased now that President Musharraf is aggressively moving to investigate it," Secretary of State Colin Powell told reporters in Washington on Tuesday.

Powell, however, refused to confirm or deny a report that Pakistani designs had helped Libya take major strides in its nuclear programme within the last two years.

"I don't have enough information at hand to answer a question quite as specific as that," he said.

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"We know that there have been cases where individuals in Pakistan have worked in these areas and we have called it to the attention of the Pakistanis in the past."

Powell added that he has discussed the issue with Musharraf and other Pakistani leaders a number of times in the past.

"And as you know, President Musharraf has announced that he will be looking into it himself very thoroughly. And to the extent that we can help him with information, we will.

"But we haven't been reluctant. I can assure you of that because I have been the one who had been talking to him about it over three years," Powell said.

Asked whether US was going to work with Islamabad if proved that Pakistan handed over such technologies to Libya or other countries while Musharraf was in office, even after September 11, Powell said, "That is just too much hypothetical to draw an answer."