Pakistani President Pervez Musharraf said this week it appeared Pakistani scientists had sold nuclear secrets abroad for personal gain, but with no official involvement.
"We are working with Pakistan... to come to the bottom of this ring of proliferators," Muhammad al-Baradei told Reuters at the World Economic Forum in Davos, Switzerland on Saturday.
"I hope we should be able in the next few weeks to come to grips with the extent and nature of that ring and dry it up as soon as possible," he added.
Al-Baradai said on Thursday anti-proliferation efforts were under great stress because of what he called a black-market network that was trading in weapons technology.
"What we are seeing is a very sophisticated network of black-market proliferators, people who are selling equipment, material underground... We are still very much in the process of investigating this network."
Pakistan says it began questioning its nuclear scientists, including the father of its atomic bomb, Abd al-Qadir Khan, after the UN nuclear agency began investigating possible links between the Pakistani and Iranian nuclear programmes.
Investigators are checking the bank accounts of scientists and administrators detained on suspicion they may have sold nuclear technology to Iran and other countries, an official said Saturday.
An Interior Ministry official, speaking on condition of anonymity, said investigators were checking bank accounts of the detainees.
He said investigators suspected that one scientist and one other person did something for personal gain, but would give no names or further details.
Musharraf said similar allegations had been made against European individuals and countries, adding that any Pakistanis found to be involved would be treated as "anti-state elements".
Pakistan is questioning its nuclear
scientist Abd al-Qadir Khan
"The Pakistani government has never, and will never proliferate," he said in Davos.
"As far as Pakistan is concerned, we are carrying out a thorough investigation of any proliferation that may have been done by individuals for their personal financial gain."
Also on Saturday in Davos, al-Baradai pressed Iran to suspend more activities related to enriching uranium, a technology that can be used to make nuclear weapons.
"I am advising them that it would be good to have a very generous, comprehensive suspension," al-Baradai told Reuters after talks with Iranian Foreign Minister Kamal Kharrazi.
"That would create confidence and it would help me and the Europeans to move forward in normalising and expanding cooperation between Iran and the international community."
He said IAEA concerns focused on the discovery by agency inspectors in Iran of equipment contaminated with highly enriched uranium, along with continued enrichment-related activities like production of centrifuges.
Kharrazi says nuclear technology
a source of pride for Iranians
Iran has blamed the contamination on parts imported from elsewhere without identifying their origin. Asked about the IAEA's concerns, Kharrazi said: "It is just a question of spare parts or something, it is minor issues."
"We have very good cooperation with the IAEA," he told reporters. "I believe the important thing is that we do not have any programme to produce weapons and this is now established."
Kharrazi said Iran's nuclear technology was a source of pride for all Iranians. "At the same time it is totally peaceful and nothing is wrong with having nuclear technology for peaceful purposes," he said.
"We have suspended the activities of uranium enrichment, but this does not mean we are going to stop it for ever. This is our right, based on the NPT, to have nuclear activities for peaceful purposes," he said, referring to the provisions in the Nuclear Non-Proliferation Treaty for the sharing of nuclear know-how.