By Simon Fraser
BBC News Online South Asia
United States forces have caught Saddam Hussein, but can they now nail their other most wanted man, Osama Bin Laden?
Bin Laden: World's most wanted spot is all his once again
The alleged mastermind of the 11 September 2001 attacks on the US has eluded capture for years.
Officials say the Saudi-born millionaire's most likely hiding place - if he is still alive - is somewhere in the mountains along the Afghan-Pakistan border.
US officials hope the Iraqi leader's capture will add fresh impetus to the hunt for Bin Laden and others.
Mullah Omar, the leader of the ousted Taleban who sheltered Bin Laden, is also reportedly in Afghanistan.
There have been no confirmed sightings of either man since the US declared its war on terror in 2001 - despite the best efforts of US intelligence and thousands of US-led troops.
The US hopes that will change.
"Saddam is no longer a problem now, so Bin Laden is the focus," US ambassador to Afghanistan Zalmay Khalilzad told reporters in the Afghan capital, Kabul.
"It shows, in the case of Iraq, that when we persisted using good intelligence and appropriate force at the right time, bringing them together did the trick.
"Here we have to do the same thing."
Years on the run
After the news from Iraq, US forces are under even greater pressure to come up with results in Afghanistan.
The US military says Sunday's dramatic news will boost the Bin Laden hunt.
Faulty intelligence has hamstrung America's Afghan campaign
But finding the al-Qaeda chief is likely to be much harder than catching the Iraqi leader, and there are key differences between the two manhunts.
Whereas Saddam Hussein had not been on the run for decades, Bin Laden has had a price on his head since 1998 and is used to life as a fugitive.
He has flitted between Africa, the Middle East and Afghanistan - unlike the Iraqi leader who rarely left his home country and was used to living in palaces.
BBC correspondent Rahimullah Yusufzai in Peshawar says the al-Qaeda leader has great experience of living in tough and rigorous conditions.
"Osama Bin Laden spent years at the frontline fighting the Russians," says our correspondent, who is among the few journalists to have interviewed Bin Laden.
Mountains versus desert
It is widely believed that Bin Laden is hiding somewhere close to the Afghanistan-Pakistan border where the mountains - full of tunnels - provide excellent bolt holes and escape routes.
He may have used them to his advantage when US troops went all out to get him at the Tora Bora cave complex in late 2001.
And the rugged terrain in Afghanistan is an effective block on US troop movements.
They simply cannot flood forces in and seal and search an area in the way they can in the Iraqi desert.
"It's totally different terrain, a different situation and a different social structure," Afghan Interior Ali Ahmad Jalali told the Associated Press.
"In the tribal areas, control is very weak."
He was referring to lawless tribal regions on the Pakistan side of the border, which have recently seen incursions by Pakistani troops seeking to check the movement of al-Qaeda and Taleban fighters fleeing Afghanistan.
Then there is the much smaller size of the US-led force in Afghanistan, where all but the capital, Kabul, is still insecure and there has been no sustained US-led campaign since the fall of the Taleban.
Fighting two campaigns may not have helped the US, either.
"If they had confined themselves to one conflict, they may have got him by now," says our correspondent.
In recent months, the Taleban and other militants have mounted increased attacks in the south and east of Afghanistan, making it much more difficult for the Americans to have it their own way.
A number of costly bombing blunders has not helped boost US popularity among locals.
And fierce local support is probably the key to why the Americans appear no nearer to finding the man they would most love to parade before the world's media.
If Bin Laden is alive and where people think he is - then he is among friends.
He used his money over the years to win local hearts and minds in the Pashtun heartlands where he may now be sheltering.
There is strong ideological backing in the area for his campaign against the West.
"That was not true of Saddam Hussein - he forced people to support him," our correspondent says.
And unlike Saddam Hussein, Bin Laden does not have to answer for years in power.
The latter was a deposed dictator with many enemies.
In the end, even returning to his home town of Tikrit could not afford him protection.
Dead or alive?
Bin Laden has had a fair deal of luck over the years - he had a close shave against Soviet troops, and lived to tell the tale after a US cruise missile attack on his camp at Khost in southern Afghanistan in 1998.
Then there was the US attack at Tora Bora, which many think he survived.
Bin Laden has a $27m bounty on his head
Saddam Hussein, too, had his fair share of good fortune until he was cornered alone in his hole at the weekend.
And like the Iraqi leader, Bin Laden has a bounty worth millions on his head.
But two years after the 11 September attacks it remains unclaimed.
Saddam Hussein, perhaps surprisingly, gave up without a fight and was taken alive.
Whether Bin Laden is captured dead or alive, or indeed ever found at all, remains to be seen.