Now that Saddam Hussein has been caught, the pressure is on to find the other top target in the war on terror. Why is it proving so hard to find Osama bin Laden?
"Bin Laden's on the run," President Bush told ABCNEWS' Diane Sawyer Tuesday in his first interview since Saddam's capture at the weekend.
The leader of the al Qaeda terror network will face a similar fate as that of the deposed Iraqi president, Bush said. "He's certainly not leading any parades these days," Bush said, referring to bin Laden. "He's probably in a hole somewhere hiding from justice. We'll get him."
The last time the U.S. military believed it knew exactly where bin Laden was hiding was two years ago, when it bombed the mountains of Tora Bora, Afghanistan.
The most recent American intelligence puts bin Laden somewhere in, or near, the mountains in the Pakistani province of Waziristan.
The region's rugged terrain, which ABCNEWS visited earlier this year, is home to fiercely independent tribes hostile to the Pakistani government or any other outside force.
The tribes and the terrain make the search for Saddam Hussein seem easy in comparison, says Akbar Ahmed, a former official in Waziristan.
"[There are] formidable fighting tribesmen who resent any outsider coming into the area," said Ahmed, who is now a professor of International Relations at American University in Washington, D.C. "Osama, if he's there, would be there as a guest. And the code of the people there is that if a guest is living there they will protect him with their lives."
Pakistan does not allow U.S. forces to operate in Waziristan, so American troops or operatives are unable to go into the marketplaces where money handlers and merchants might provide the kind of clues that led to Saddam Hussein's hideout in Iraq.
"We have to work through the Pakistanis," said Richard Clarke, an ABCNEWS consultant who was a national security adviser at the White House before retiring earlier this year, "and in Pakistan there are vast areas that are hostile to even the Pakistanis. So it's very, very difficult to do the kind of controlled search we did in Iraq."
U.S. satellites constantly cover the area, looking for movement, vehicle caravans and unusual activity in certain Waziristan villages. But satellite analysts say the coming winter months mean more cloud cover blocking the view from imagery, but also present certain opportunities.
"You'll be able to see fresh tracks in the snow," said Tim Brown, an imagery analyst with GlobalSecurity.org, and be able to see how often a particular area has been visited.
U.S. officials believe they've narrowed bin Laden's whereabouts to a 40-square-mile area of Waziristan, but say it won't mean much without the kind of real-time human intelligence that led to the capture of Saddam Hussein.
"It took us about seven months of looking to find Hussein, and it so far has taken us more like 30 months going after bin Laden and we're still nowhere near being able to develop a methodology for getting bin Laden," said Richard Clarke. "I think the chances of getting bin Laden are pretty remote."
U.S. and coalition troops across the border in Afghanistan have recently been trained in non-lethal methods of capture and equipped with canisters of knockout gas. But officials say the most likely scenario would involve a sighting of bin Laden by air or satellite, followed by a massive missile strike.