President Pervez Musharraf, Interior Minister Faisal Salih Hayat and Information Minister Shaikh Rashid have all declared this week that those found guilty of selling nuclear technology to foreign countries will be "severely" punished.
Their pledges raise the awkward prospect of charging some of Pakistan's most revered men, elevated to national hero status for their contributions in making Pakistan a nuclear power.
"This is a very sensitive matter," Hayat was quoted as saying in the Dawn newspaper on Tuesday.
"If some of those who were called national heroes have done this and are being exposed, the nation has the right to see the true faces of those who have compromised Pakistan's national interest and used its assets for personal gains."
Families of detained scientists
have held several protests
Already the investigation, which has seen at least 14 top nuclear scientists and administrators interrogated, has infuriated their families and Islamist organisations.
They have held almost daily protests against the treatment of those questioned in recent weeks.
Rashid said the probe was now focussing on three scientists and four military officials.
"There are seven people under investigation now, four of them are associated with security matters," he told a press conference late on Monday.
Of them, "one or two" may be guilty, he said. "There may be one or two who indulged in proliferation for personal commercial gains.
"Those found involved will be dealt with severely."
Khan in the dock
The widely-revered "father" of Pakistan's nuclear programme Abd al-Qadir Khan, a metallurgist who was charged with stealing the blueprints for uranium centrifuges while working in the Netherlands in the 1970s, is among those to have been questioned.
Abd al- Qadir Khan is a hugely
respected figure in Pakistan
But as one of Pakistan's most respected national heroes, he was not taken into custody as the other 13 were.
The Asian Wall Street Journal reported on Monday that Khan, 66, might be prosecuted under the Official Secrets Act, according to an unnamed government official.
Rashid refused to comment on the report saying Khan had not been placed under any restrictions. He said he would meet Khan later on Tuesday.
The probe would be finished before Eid-al Adha next week, Rashid added.
Musharraf vows action
Musharraf, who told the BBC on Monday that guilty proliferators would be harshly punished, repeated the promise to a high-level meeting later, Rashid said.
"The meeting reiterated that those found guilty will be dealt with severely and those found innocent will be allowed to go home," the minister said.
Musharraf has pledged to come
down heavily on proliferators
The government probe, under way since December, was prompted by information from the IAEA and subsequent trips by Pakistani investigators to Iran, Libya and IAEA headquarters in Vienna.
Musharraf and other officials have repeatedly said that no
government or military institutions are involved in sharing nuclear techonology and know-how.
But observers are sceptical that such strategic security information could have been passed overseas without higher approval.
"The transfer of such materials is impossible without explicit permission from the security apparatus that constantly surrounds the nuclear establishment, installations and personnel," Pervez Hoodbhoy, professor of physics at Islamabad's Quaid-e-Azam University, said.