Tracking down Usama bin Laden has proven tougher than getting to Abu Musab al-Zarqawi because the top Al Qaeda leader keeps a lower profile, surrounds himself with far more faithful followers and has more places to hide, intelligence experts say.
The mastermind of the Sept. 11 attacks avoids using satellite phones and the Internet. He is believed to be holed up along Pakistan's border with Afghan in rugged, remote terrain, protected by loyal tribesmen.
Al-Zarqawi was killed Wednesday just 30 miles from the Iraqi capital. In late April, he was featured in a videotape firing a machine gun in the desert and talking to insurgents.
"Usama bin Laden is a far more difficult leader of Al Qaeda to be caught as compared to al-Zarqawi," said Talat Masood, a retired Pakistan army general. "Firstly, bin Laden is not involved in day-to-day operations and we believe that he enjoys the support of much more loyal people."
Al-Zarqawi had a $25 million bounty on his head — the same amount offered by the United States for information leading to bin Laden.
Henry Crumpton, the U.S. ambassador in charge of counterterrorism, last month called parts of Pakistan's border region a "safe haven" for militants. He said bin Laden was more likely to be hiding there than in Afghanistan.
According to a senior Pakistani security official, bin Laden avoids using the Internet or satellite phones.
Bin Laden "has seen the fate of those who used satellite phones. He has seen that many such people were arrested by us, and they included some close associates of the Al Qaeda chief," the official said. He spoke on condition of anonymity because of the sensitive nature of his job.
The official said Pakistani forces, in cooperation with U.S.-led coalition troops in Afghanistan, were working to get closer to bin Laden, but "so far we don't have any clue on his whereabouts."
The Afghan Defense Ministry spokesman, Gen. Zahir Azimi, said he hopes al-Zarqawi's death will invigorate the hunt for bin Laden. "The hunt for Osama continues," he said.
A written statement purportedly from supreme Taliban leader Mullah Omar on Friday mourned al-Zarqawi and vowed to keep fighting in Afghanistan.
Omar was "deeply sad over the martyrdom of Abu Musab al-Zarqawi" but his death would not weaken the resistance in Iraq, "as it is the people's resistance and every youth can become al-Zarqawi," the Pashto-language statement said.
"I want to assure the Muslims across the world that we will not stop our struggle ."
More than 20,000 U.S.-led coalition soldiers are deployed in Afghanistan pursuing Taliban and Al Qaeda fighters. Pakistan has 80,000 soldiers in its Waziristan tribal region, the area regarded as the most likely hiding place for bin Laden and his top deputy, Ayman al-Zawahri.
The two leaders are now fairly disconnected from Al Qaeda's activities, said a senior Western diplomat in Islamabad, who agreed to discuss the matter only if not quoted by name because of the sensitive topic.
"They've been able to escape detection as they aren't communicating and aren't effectively involved in Al Qaeda operations. It makes it very hard to run them down, but moves them significantly from an operational role to a symbolic one," he said.
"It doesn't make any sense to talk of getting closer to them. One day they will be killed or captured, and it will happen like that," the diplomat said, snapping his fingers.