Deputy National Security Advisor for Homeland Security and Counterterrorism, and Assistant to the US President John Brennan said that Osama bin Laden was involved in a firefight with US forces when he was killed on Sunday in Pakistan.Speaking at a White House press conference about the operation, Brennan went into detail about the operation in which Osama was killed, ranging from what information was shared with Pakistan to the level of information US President Barack Obama was able to view in real time during the operation.The White House official made clear, contrary to reports emanating from Pakistan that the United States did not notify Pakistan of the operation until US aircraft were safely out of Pakistani airspace, risking engagement with Pakistani jet fighters that were scrambled during the operation.The Pakistanis, Brennan said, "had no idea who was in their airspace ... thankfully, there was no engagement. This was done well and no Pakistani forces were engaged."Asked about details of the raid itself, Brennan said that bin Laden likely used his wife as a human shield when US special forces soldiers located him towards the end of the 40-minute raid. One of bin Laden's wife was killed in the raid.Obama, he said, was in the White House situation room during the operation and was following developments "in real time," though he would not expand on what that meant.Asked how bin Laden was able to live in Pakistan for so long without authorities in that country being aware of his presence, Brennan described the situation as one where bin Laden was "hiding in plain sight.""We're looking at how he was able to hold out there for so long and if there was support in Pakistan that allowed him to do that," he said, adding that "its inconceiveable that that [Osama bin Laden] did not have a support system in the country that allowed him to stay [there] for a sustained period of time."Regarding the question if there was a standing order to kill bin Laden or if efforts were made to capture him alive, Brennan said "the goal was to prepare for all contingencies. If we had an opportunity to take him alive, we would have."Intelligence information said bin Laden would oppose attempts to capture him, Brennan added, "...and he did that. But we were certainly prepared for the [remote] possibility of capturing him alive."