The admission by Pakistan's nuclear founder that he spread weapons technology to Iran (search), Libya (search) and North Korea raised questions Monday about whether military figures knew of the transfers.
Officials said for the first time that two former army chiefs have been questioned in the scandal but weren't implicated.
The revelations Monday came as Pakistan (search) completed its investigation that began in late November after Iran provided relevant information to the U.N. nuclear watchdog, the officials said.
President Gen. Pervez Musharraf (search) was expected to announce the results of the nuclear probe in an address to the nation after a period of national holidays ends Thursday.
The seven key suspects include scientists and security officials from the country's top nuclear facility.
Chief among them is Abdul Qadeer Khan (search), long seen as a hero in Pakistan for creating the Islamic world's first nuclear bomb. Officials said he confessed in a written statement to spreading nuclear "drawings and machinery" to Iran, Libya and North Korea for about a decade starting in the late 1980s.
Khan was fired Saturday as a scientific adviser to the prime minister. Perhaps to forestall a public backlash over his dismissal, two top military officials briefed Pakistani journalists about his confession, submitted to investigators late last week.
According to journalists invited to the briefing, Khan told investigators he had provided the secrets to other Muslim countries -- Iran and Libya -- so they could become nuclear powers. The transfer to North Korea "was to divert attention of the international community from Pakistan."
Officials said Khan acted for personal gain but that he denied it.
In recent days, newspapers have reported Khan had a vast array of real estate holdings, and even used a C-130 military transport plane -- which landed in Libya with Khan's top aide on board -- to ship furniture to a hotel he owned in Timbuktu, Mali.
Pakistani authorities have conceded there was a security lapse but deny there had been any official knowledge of Khan's actions. But there are growing doubts over how top military officers overseeing the nuclear program couldn't have known about the spread of technology to at least three countries.
A government official said "questions have been put" to two former army chiefs to check information provided by Khan and other suspects -- the first time that such top figures have been quizzed in the proliferation probe.
Gen. Jehangir Karamat and Gen. Mirza Aslam Beg, a nationalist and strong advocate of a strategic alliance with Iran during his tenure, denied they had authorized nuclear transfers, the official said.
Beg has said Pakistani scientists may have spread nuclear secrets to Iran and Libya, but that it was "no crime" and the probe was a mistake and a sign the government was caving to Western pressure.
Military officials told journalists that authorities didn't closely scrutinize what was going out of the nuclear lab because Khan was a trusted figure.
The revelations that the top nuclear scientist in Pakistan -- now a key ally in the U.S. war on terror -- sold sensitive technology to two nations among President Bush's "axis of evil" alarmed the international community.
But analysts said Musharraf's apparent willingness to come clean about the shady past of Pakistan's covert nuclear program would count in his favor. He has won foreign plaudits for his opposition to Islamic extremism and eagerness for peace with India, Pakistan's nuclear rival.
Much depends on what comes next. It is not clear what will happen to Khan.
"Pakistan needs to show the world that it is a responsible nuclear power and this happened in the past," said Talat Masood, a military and political analyst. "It has to reassure the international community that it is investigating thoroughly and action will be taken against those involved, either administratively, legally or both."
A public prosecution, however, would risk airing secrets about Pakistan's covert nuclear program that originated in the 1970s and relied on black market suppliers to circumvent international restrictions.