Al-Qaeda and Taliban leaders Osama Bin Laden and Mullah Mohammad Omar and their top commanders are hiding in Pakistan, posing a "huge challenge" to the security of the country and neighboring Afghanistan, a senior US administration official said on Friday.
"There is no question that the iconic leaders of Al-Qaeda -- (Ayman al-) Zawahiri, bin Laden ... are in the tribal areas of Pakistan," the official said at a media briefing.
"We believe that the Taliban's shura (consultation) council leaders led by Mullah Omar reside in Quetta in Pakistan," he said, referring to the capital of rugged Baluchistan province bordering Afghanistan.
The sanctuaries were not only helping Taliban fight the insurgency against Afghan President Hamid Karzai's administration, which is backed by US and NATO troops, but also posing a threat to Pakistan and beyond central Asia, the official said.
"There is a threat to the east into (Pakistan), in the west into Afghanistan and there is threat beyond Central Asia to the extent that Al-Qaeda has reach," he said, speaking on condition of anonymity.
"Just as Mullah Omar is giving strategic direction for the Taliban from Quetta, the Al-Qaeda senior leadership is in the FATA doing its planning," he said.
Pakistan's federally administrated tribal areas (FATA) borders Afghanistan.
It is among the clearest statements by the United States on the location of the Al-Qaeda and Taliban leaders.
Pakistan has repeatedly denied the presence of bin Laden or Omar in its territory. Washington has placed multi-million dollar rewards for their heads.
The Taliban was ousted in a US-led invasion in 2001, after the September 11 terror attacks masterminded by bin Laden, who was provided sanctuary by the extremist regime in Kabul at that time.
More than six years after the ouster, US and NATO-led troops are still waging an uphill battle against the Taliban.
The US official said the United States had seen clear links between the insurgency in Afghanistan and Pakistan through the Pashtun group, an ethnic minority mostly living along the troubled Afghan-Pakistani border.
"We also know that there are very clear Pashtun tribal links up through the FATA, especially in north and south Waziristan, where Pashtuns who live in Pakistan are supporting Pashtuns, who are fighting in Afghanistan.
"In some cases, they are the one and same people -- they live in Pakistan, they commute to the fight, they fight for a while in Afghanistan and retreat back into safe haven inside Waziristan," the official said.
He said that the Taliban and Al-Qaeda over the last six months had not only taken up their fight from their "safe haven" west into Afghanistan but also into the east, into the areas of Pakistan itself.
Underscoring concerns over the militant groups' logistical gains was the December assassination of former premier Benazir Bhutto in Rawalpindi, a city where the army has its headquarters, about seven miles from the capital Islamabad, he said.
CIA Director Michael Hayden said last month that suspected Al-Qaeda militants and allies of Pakistani tribal leader Baitullah Mehsud were behind Bhutto's murder and warned of a "newly active alliance" between Pakistani and international terrorists against President Pervez Musharraf's administration.
"Now you have a Pashtun-based insurgency that is fighting to regain control of Afghanistan, retaining safe haven, protecting its safe haven in the FATA and in some cases has now declared open hostilities with the Pakistani government as well," the US official said.
"So, you have got this sort of layering of insurgencies here that really makes this both geographically, politically and militarily a very complex setting," he said. "It is a huge challenge."
The official also said that US Secretary of State Condoleezza Rice, her British counterpart David Miliband and Karzai had discussed in Kabul this week the appointment of a new United Nations envoy to Afghanistan.
Karzai had earlier refused to endorse senior British politician Paddy Ashdown, who was also the international community's former envoy to Bosnia.
"We are looking for someone who can work well inside the UN structure, someone who can bring coherence to this extremely complex mission and someone who can serve as Karzai's teammate, partner," the official said.