"What's important is that we learn a lesson from what has happened and take action to ensure that there isn't such similar proliferation in future," Straw told a press conference after an hour-long meeting with President Pervez Musharraf.

"But I am satisfied about the progress which the Pakistani authorities are making and the cooperation which they are providing to the International Atomic Energy Agency."

Straw discussed the proliferation scandal with Musharraf at the start of a three-day visit to the Pakistani capital, one month after the founder of its nuclear program Abdul Qadeer Khan publicly confessed to selling nuclear secrets to Iran, Libya and North Korea.

Musharraf's decision to pardon Khan instead of prosecuting him, and to forbid an inquiry by international experts, has drawn criticism, amid yet-to-be proven allegations that Pakistan's army had a role in the sale of nuclear technology.

Straw said the treatment of A.Q. Khan was Pakistan's business.

"What happens to those involved is a matter for the Pakistani authorities and not for us," he told reporters.

Straw, on his fifth visit to Pakistan in two and a half years, also discussed the war on terrorism, peace moves with India, Afghan reconstruction and Pakistan's bid to re-enter the Commonwealth after a suspension of more than four years.

He described his talks with Musharraf as "thorough."

Straw, who arrived in the Pakistani capital late Wednesday for a three-day official visit, spent one hour with Musharraf at army headquarters in Rawalpindi, next to Islamabad.

Earlier he met Foreign Minister Kurshid Mahmud Kasuri and will later meet Prime Minister Zafarullah Jamali and Interior Minister Faisal Saleh Hayat, officials said.

A senior Pakistani official said earlier that he would discuss Islamabad's four-month probe into the sale of nuclear equipment and designs by Pakistani scientists to Iran, Libya and North Korea.

The probe, launched late November following revelations by Iran to the International Atomic Energy Agency (IAEA), resulted in a public confession of proliferation by the architect of Pakistan's nuclear program Abdul Qadeer Khan.