The United States thinks that Pakistan is taking serious efforts "to end the activities of a dangerous network."
"It's up to the Government of Pakistan to take the necessary measures to ensure that this kind of proliferation will not happen again," State Department spokesman said on Thursday.
Responding to a query on confession by Dr A.Q. Khan and that he has been pardoned, Richard Boucher said: "It's important that those measures be comprehensive and they be enduring."
"We'd also expect that Pakistan will share information that they're unearthing in their ongoing investigation with the international community."
Boucher reviewed the situation "and what we see and what we expect.
"First, I think the actions that Pakistan has been taking in regard to this investigation and uncovering information about the actions of various Pakistanis need to be seen in the context of the overall international effort on - against proliferation of weapons of mass destruction."
"The spread of nuclear weapons and technology is indeed a matter of global concern. The United States has urged all nations that have this technology to take precautions to ensure that it is properly controlled, that it does not fall in the hands of rogue states, non-state actors and individuals.
"And that's why we have said that we value the commitments President Musharraf has made to prevent the expertise in Pakistan from reaching other places and other countries and other nations, and we have welcomed the investigation that they have undertaken into reports that such
activities have occurred."
He said, "as far as the specifics of what happens to Dr Khan, other than making sure that he and whatever other individuals or networks in Pakistan might have been involved in this trade don't transfer anything again, as far as the specifics of sentencing or pardons or whatever, that really is a matter for Pakistan to decide, and they'll take, I'm sure, appropriate measures to ensure that he's - he and his associates are no longer able to endanger the international community."
He told a questioner: "I think it's a matter that we think what's important in this case is really two things: one is that the network and the individuals who were doing this in Pakistan or from Pakistan be found out stopped, prevented from making any such transfers again; and second of all, that the information that they develop in their information is shared with the international community, because the international community as a whole needs to go after this network that extends far beyond Pakistan in some cases."
He, however, said: "No, it's not okay. No. It's for governments to find out and prevent this kind of thing."
"But what penalties, sanctions, controls or steps are used to prevent it from happening again - those are up for individual governments to decide."
He said: "it's up to the Pakistani government to make sure that this sort of thing doesn't happen again."
Boucher said: "I think, the Government of Pakistan itself says that the - the matter is ongoing; and that the investigation is ongoing."
Non-proliferation, he said, "is and must be an ongoing effort. It is for all of us, whether it's this particular network or anything other than this particular network. But in terms of the specific investigation, I think the Pakistanis, themselves, acknowledge that this is an ongoing investigation that's not finished yet."
He said the US has spoken quite clearly on the importance of the steps Libya has taken to disclose, dismantle, destroy all its activities in the area of weapons of mass destruction. These are important decisions from Libya, and we believe those do, in fact, serve as a model for others that others should follow.
He said: "The facts are clear that what Libya did is good for the international community."
The State Department spokesman said that " I'm saying what's important here is that the Government of Pakistan take steps to make sure that Pakistan won't be a source of proliferation, either with materials, equipment, or especially with the intangibles, the expertise that can help other countries develop weapons of mass destruction."
"We see Pakistan taking steps that go to that end. We see Pakistan developing information as part of an investigation that is useful to the whole international community to go after this private network, this network of people sharing materials, information and expertise. And we would expect them to share that information with the international community. Those are the important things."