Details about the joint session of the Senate and National Assembly held behind closed doors on Friday continue to emerge in the media here.
A report in The Express Tribune newspaper said today that a "visibly angry" ISI chief Lt Gen Ahmed Shuja Pasha snubbed Khan, the Leader of Opposition, during the session.
The incident occurred after top military officials, including Pasha, briefed the lawmakers about the May 2 US raid in the garrison city of Abbottabad that killed al-Qaeda chief Osama bin Laden.
Khan rose in his seat to make a speech as a question-and-answer session was to begin.
Pasha, who was at the receiving end of several fiery speeches in Parliament by Khan, claimed he knew why he was being targeted by the Leader of Opposition.
Pasha alleged that Khan had asked him for a personal favour, which he, as the ISI chief, had refused to extend, The Express Tribune reported.
However, Pasha said he would not reveal what the favour was on the floor of the House though he would do so if asked outside Parliament.
An embarrassed Khan was reportedly taken aback as Pasha continued his "counter-attack."
Pasha kept on grilling Khan, asking the PML-N leader if he knew about the effects of his recent tirades in Parliament.
Pasha told the House that, on a recent trip to the US, he was told by CIA chief Leon Panetta: "Look, General Pasha how can we trust you when your own country's opposition leader is saying that you cannot be believed?"
Pasha said that, despite having answers to all questions during that session, he did not have an answer to the question from the CIA chief.
"What should I tell the Americans?" Pasha was quoted as saying.