Pakistan, which was a "major source" of nuclear proliferation in the past, has been invited to the US-hosted Nuclear Security Summit, as America wants it to be part of the solution to the problem, a top Obama Administration official said on Saturday.
"We want to see Pakistan be part of the solution in the future. It has been part of the problem in the past. Pakistan has been a source of proliferation, and at various times in the past we have taken specific steps against Pakistan as a result," Assistant Secretary of State for Public Affairs P J Crowley told the media.
He said Pakistan had recently demonstrated its willingness to help the international community to shut down the A Q Khan network.
"We still have questions about that and we still pursue those with Pakistan," Crowley said in response to a question.
The state department spokesperson said Pakistan, of late, has demonstrated that it can secure its own, nuclear weapons program, and the US has confidence in the steps that Pakistan has taken.
Responding to a question that Pakistan is the country in which the greatest nuclear proliferation has ever taken place under A Q Khan, Crowley said: "You're quite right, Pakistan has been a source of concern in the past and we have had significant discussions with Pakistan on these issues.
"But if we're going to strengthen the nonproliferation regime going forward, we want to see, Pakistan invested in this process."
"To the extent that other countries demonstrate through their cooperation with the international community that they are willing to assume that same responsibility, then the door would be open for further cooperation. But in the case of the three countries that were noted earlier, they have noted right now for their refusal to cooperate with the international community."
This is the reason why, Crowley said, three countries Iran, North Korea and Syria, were not invited to the Nuclear Security Summit.
The governments that will be in attendance next week have shown a willingness to work cooperatively within the international community to strengthen, the security of nuclear weapons and nuclear know-how, he said.
"The three countries that you just cited -- North Korea, Iran and Syria -- have steadfastly either refused or failed to cooperate effectively with the International Atomic Energy Agency. So we are strengthening the nonproliferation regime expressly to be able to deal with, those countries that pose significant challenges, you know, to our long-term security," Crowley said.