Kabul, May 6 : Pakistan is not doing enough to help root out Taliban and al Qaeda leaders who have found safe haven in its lawless tribal lands along the Afghan border, a senior US security official said today.
Most al Qaeda and Taliban leaders are in Pakistan, and while the United States did not know where Osama bin Laden was hiding, he was probably on the Pakistan side of the border, said Henry Crumpton, State Department coordinator for counterterrorism.
Pakistan, a vital US security ally, has arrested hundreds of al Qaeda members and lost hundreds of its troops battling militants.
But Afghan officials have complained insurgents were able to gather support and launch raids from the safety of Pakistani territory.
Violence has intensified in parts of Afghanistan in recent months to its worst level since US and Afghan opposition forces ousted the Taliban in 2001.
''Has Pakistan done enough? I think the answer is 'no','' Crumpton told a news briefing in the Afghan capital, Kabul.
''Not only al Qaeda, but Taliban leadership are primarily in Pakistan, and the Pakistanis know that,'' Crumpton added.
Relations between Afghanistan and Pakistan deteriorate sharply this year when Afghanistan again said Taliban leaders were operating from Pakistan.
Pakistan rejects accusations it helps the Taliban.
Crumpton said eliminating militant safe havens in Pakistan's tribal lands was crucial.
''It's something we have to help the Pakistanis work through because it cannot remain a safe haven for enemy forces,'' he said.
''Right now, parts of Pakistan are, indeed, that.'' The militants are fighting to oust foreign troops and the government. They have launched a wave of roadside and suicide bombings, attacks and assassinations in recent months.
''We are concerned by the increase in violence in the south and east,'' Crumpton said.
''We see the alliance of al Qaeda and elements of the Taliban, and, increasingly, narco-traffickers a confluence of allies -- is a cause for concern,'' he said.
More than 7,000 NATO troops, most from Britain, Canada and the Netherlands, are in, or soon arriving in, the dangerous Afghan south.
NATO will take command there from a separate US-led force in July. The deployments will let the United States cut its Afghan force by several thousand, to about 16,500.
Critics say the NATO troops risk getting bogged down in a elentless insurgency, funded in part by the huge opium trade and sustained by havens in Pakistan.