WASHINGTON - US President Barack Obama monitored the raid that left Osama bin Laden dead in real time but an aide wouldnt say whether he watched it unfold via live video. John Brennan, assistant to the president for homeland security and counterterrorism, told reporters Monday the president and other advisers gathered Sunday afternoon before the operation got started in Pakistan and we were able to monitor in real time the progress of the operation from its commencement to its time on target to the extraction of the remains and to then the egress of the target. It was probably one of the most anxiety-filled periods of time, I think, in the lives of the people who were assembled here yesterday, Brennan said. The minutes passed like days. And the president was very concerned about the security of our personnel. That was what was on his mind throughout. And we wanted to make sure that we were able to get through this and accomplish the mission. Brennan described a tense situation marked by periods of silence with a lot of people holding their breath. There was, he said, a tremendous sigh of relief that what we believed and who we believed was in that compound actually was in that compound and was found. Asked if the president was able to see what was happening at the compound where the al-Qaeda leader was killed by Navy Seals, Brennan declined to provide details. We were able to monitor the situation in real time and were able to have regular updates and to ensure that we had real-time visibility into the progress of the operation, he said. Im not going to go into details about what type of visuals we had or what type of feeds that were there, but it was it gave us the ability to actually track it on an ongoing basis. He gave a similar answer when asked if those in the room could hear shots being fired. But Brennan did give an indication some sort of visual contact was maintained when he talked about one US helicopter that was damaged and had to be destroyed. They were able to conduct the operation as they were preparing to do, he said. But seeing that helicopter in a place and in a condition that it wasnt supposed to be, I think that was at least for me, and I know for the other people in theroom the concern we had that now were having to go to the contingency plan. And thankfully, they were able to carry out that contingency plan. Obama said the death of bin Laden was one of several moments this year that have brought us together as an American family, whether it was the tragedy in Tucson or, most recently, our unified response to the terrible storms that have taken place in the south. Earlier on Monday, the White House released a list of world leaders Obama has spoke with by telephone who expressed their congratulations on the operation. The list included the leaders of Mexico, Great Britain, Germany, France and Israel.