The president made the comments in an interview that aired Sunday night on CBS' "60 Minutes." Obama said he was only 45 to 55 percent sure that bin Laden was even in the compound.
"It was a very tense situation," said Obama. "As nervous as I was about this whole process, the one thing I didn't lose sleep over was the possibility of taking bin Laden out."
Obama said he has seen the death photos of bin Laden. The U.S. Department of Defense released five videos Saturday showing bin Laden in propaganda tapes. A less-than-flattering video showed the 54-year-old terrorist seated on the floor, watching television while wrapped in a wool blanket and wearing a knit cap.
Pakistan/U.S. relations
Bin Laden was killed in a Pakistani home where he'd lived for up to six years, only two and a half hour's drive outside the capital. This has sparked suspicion that Pakistani officials knew where the al Qaeda leader was hiding and may have been helping him.
"We don't know whether there might have been people inside government, outside government, that's something we have to investigate," said Obama. "And more importantly the Pakistani government has to investigate. These are questions we're not going to be able to answer three or four days after the event. It's going to take some time for us to exploit the intelligence we were able to gather on site."
A senior Pakistani official told ABC News that based on years of experience he believes: "Elements of Pakistani intelligence, probably rogue or retired, were involved in aiding, abetting and sheltering the leader of al Qaeda."
Media in Pakistan have reported a name they said is that of the CIA station chief in Islamabad. The Associated Press however is reporting that the alleged name is incorrect. This is the second time in six months that the Pakistani media have reported the alleged name of the CIA station chief.
Monday, Pakistan's Prime Minister Yousuf Raza Gilani adamantly rejected allegations of a support network.
"It is disingenuous for anyone to blame Pakistan or state institutions of Pakistan, including the ISI and the armed forces, for being in cahoots with al Qaeda," said Gilani. "Allegations of complicity or incompetence are absurd. Pakistan is not the birthplace of al Qaeda. We did not invite Osama bin Laden to Pakistan or even to Afghanistan."
Gilani agreed that the failure to find bin Laden was a mistake. But he insisted it wasn't Pakistan's alone.
"Yes, there has been an intelligence failure," said Gilani. "It is not only ours but of all the intelligence agencies of the world."
He warned the U.S. against launching future such attacks.
"Unilateralism runs the inherent risk of serious consequences," said Gilani. "Pakistan reserves the right to retaliate with full force. No one should underestimate the resolve and capability of our nation and armed forces to defend our sacred homeland."
But he insisted that relations with the U.S. remain strong and the two countries have worked well together during this period of crisis. He also praised the result of the raid.
"Osama bin Laden was the most wanted terrorist and enemy number one of the civilized world," said Gilani. "Elimination of Osama bin Laden, who launched waves after waves of terrorist attacks against innocent Pakistanis, is indeed justice done."
He said that the army will conduct an inquiry into the raid and military officials will brief parliament later in May.
Osama bin Laden's wives
The U.S. is trying to get access to bin Laden's three widows. Authorities want to ask them about the possibility that Pakistan harbored bin Laden.
The women, along with their children, are believed to be in Pakistani army custody. U.S. authorities are also hoping to get any intelligence material that may have been left behind at the compound.
The Associated Press and ABC News contributed to this story
