In the first direct comment on the reason for rejection of a civilian nuclear deal for Pakistan on the lines of the historic Indo-US agreeement, the US on Wednesday said it was because of that country's "proliferation history."

"Well, obviously, the Pakistanis want to continue to have a good relationship with us. It's not going to be possible for us to have a civil nuclear relationship with Pakistan of the type that we've just announced with India. Because of history, because of their proliferation history," Under Secretary of State for Political Affairs Nicholas Burns told CBS channel's 'Charlie Rose Show.'

Burns' comment was an obvious reference to the global nuclear proliferation network carried out by the disgraced Pakistani nuclear scientist A Q Khan.

Burns also said India's military programme was never the focus of the landmark Indo-US civil nuclear agreement and brushed aside notions that it was meant to contain China.