WASHINGTON (Reuters) - Osama bin Ladens death was cheered by scores of Americans, but his demise is unlikely to mend the US administrations severely frayed ties with Islamabad or ease fierce fighting in Afghanistan. US President Barack Obama announced late on Sunday that the al Qaeda leader was shot to death in Abbottabad, near Pakistans capital, ending the United States decade-long quest to snare the man behind the Sept. 11 attacks. Analysts and officials warned the United States was unlikely to see a swift end to its troubles in a region where American policy has, for the last decade, been driven by its fears of another such attack. Its important for US and European allies to remember that theres still a lot of work to do, a senior Western official in Kabul said on condition of anonymity. This doesnt change the fact that theres an insurgency that is an existential threat to the government of Afghanistan, and that Pakistan is a basket-case that is a threat to regional security, the official said. The Obama administration is grappling with record violence in Afghanistan even as it prepares to begin pulling out some of the 100,000 US soldiers this July. Ties with Islamabad, an important if unreliable US ally against militants, have strained close to a breaking point over US drone attacks on insurgents along Pakistans border with Afghanistan and over Pakistans six-week imprisonment of a CIA contractor earlier this year. Admiral Mike Mullen, chairman of the US militarys Joint Chiefs of Staff, last month accused Pakistans intelligence agency of maintaining ties with militants targeting US troops in Afghanistan. Obama, speaking in a hastily announced late-night new conference, said cooperation from Pakistan had helped lead US forces to bin Laden. But American and Pakistani sources familiar with details of the operation said US forces snared bin Laden virtually behind Pakistans back. That could be a sign of mounting frustration in Washington with Pakistan, one of the top non-NATO recipients of US military aid, over what US officials say is Islamabads unwillingness to do enough against militants who launch attacks against American soldiers in Afghanistan. Imtiaz Gul, a security analyst in Islamabad, said bin Ladens capture in a town several hours drive from his countrys was a serious blow to the credibility of Pakistan. While Obama called it a good and historic day for both countries, he also chided Pakistan, urging it to continue to join us in the fight. SOLDIERING ON IN AFGHANISTAN: The euphoria in Washington was hard to find in Afghanistan, where about 130,000 foreign troops are bracing for a bloody spring offensive for a resilient Taliban. The Obama administration has credited a surge of US troops into Afghanistan with helping push the Taliban out of key areas, but the Pentagon is also warning that violence is likely to keep getting worse. Some analysts said bin Ladens death could encourage the Taliban, which hosted bin Laden before Sept. 11, to split from al Qaeda and support the kind of political settlement many see as the only option to ending almost a decade of war in Afghanistan. At the least, bin Ladens death will cause soul-searching among the Taliban leadership as they weigh the utility of remaining allied to an organization that has lost its founding leader, said Lisa Curtis, a regional expert with the Heritage Foundation in Washington. While it is not expected to change the outlook for US efforts to end to a long, unpopular war, bin Ladens death could increase pressure on Obama as he looks toward his 2012 reelection bid and seeks to rein in spending. There is no doubt this will increase questions about whether the United States could accelerate its drawdown, the Western official said. More important than bin Ladens fate in shaping the Wests disentanglement from Afghanistan may be the speed in which it can develop a capable local fighting force. Critics doubt whether Afghan forces, growing but still plagued by attrition and illiteracy, will be ready to take over from foreign forces by the end of 2014 as planned.