The war in Afghanistan is the period in which the United States invaded the country after the September 11 attacks, supported initially by close allies, and eventually by the wider North Atlantic Treaty Organization, beginning in 2003. The conflict is also known as the U.S. war in Afghanistan. It followed the Afghan Civil War's 1996–2001 phase. Its public aims were to dismantle al-Qaeda, and to deny it a safe base of operations in Afghanistan by removing the Taliban from power. Key allies supported the U.S. from the start, including the United Kingdom. In August 2003, NATO became involved as an alliance, taking the helm of the International Security Assistance Force. On 28 December 2014, NATO formally ended combat operations in Afghanistan and transferred full security responsibility to the Afghan government, via a ceremony in Kabul. U.S. President George W. Bush demanded that the Taliban hand over Osama bin Laden and expel al-Qaeda, bin Laden had already been wanted by the U.N. since 1999. The Taliban declined to extradite him unless given what they deemed convincing evidence of his involvement in the 9/11 attacks and ignored demands to shut down terrorist bases and hand over other terrorist suspects apart from bin Laden. The request was dismissed by the U.S. as a meaningless delaying tactic and it launched Operation Enduring Freedom on 7 October 2001 with the United Kingdom. The two were later joined by other forces, including the Northern Alliance. The U.S. and its allies drove the Taliban from power and built military bases near major cities across the country. Most al-Qaeda and Taliban were not captured, escaping to neighboring Pakistan or retreating to rural or remote mountainous regions. In December 2001, the United Nations Security Council established the International Security Assistance Force (ISAF), to assist the Afghan interim authorities with securing Kabul. At the Bonn Conference in December 2001, Hamid Karzai was selected to head the Afghan Interim Administration, which after a 2002 loya jirga in Kabul became the Afghan Transitional Administration. In the popular elections of 2004, Karzai was elected president of the country, now named the Islamic Republic of Afghanistan. In 2003, NATO assumed leadership of ISAF, with troops from 43 countries. NATO members provided the core of the force. One portion of U.S. forces in Afghanistan operated under NATO command; the rest remained under direct U.S. command. Taliban leader Mullah Omar reorganized the movement, and in 2003, launched an insurgency against the government and ISAF. Though vastly outgunned and outnumbered, the Taliban insurgents, most notably the Haqqani Network and Hezb-e-Islami Gulbuddin, have waged asymmetric warfare with guerilla raids and ambushes in the countryside, suicide attacks against urban targets and turncoat killings against coalition forces. The Taliban exploited weaknesses in the Afghan government, among the most corrupt in the world, to reassert influence across rural areas of southern and eastern Afghanistan. ISAF responded in 2006 by increasing troops for counterinsurgency operations to "clear and hold" villages and "nation building" projects to "win hearts and minds". While ISAF continued to battle the Taliban insurgency, fighting crossed into neighboring North-West Pakistan. In 2004, the Pakistani Army began to clash with local tribes hosting al-Qaeda and Taliban militants. The US military launched drone attacks in Pakistan to kill insurgent leaders. This resulted in the start of an insurgency in Waziristan in 2007. On 2 May 2011, United States Navy SEALs killed Osama bin Laden in Abbotabad, Pakistan. In May 2012, NATO leaders endorsed an exit strategy for withdrawing their forces. UN-backed peace talks have since taken place between the Afghan government and the Taliban. In May 2014, the United States announced that its combat operations would end in 2014, leaving just a small residual force in the country until the end of 2016. As of 2015, tens of thousands of people have been killed in the war. Over 4,000 ISAF soldiers and civilian contractors as well as over 15,000 Afghan national security forces members have been killed. In October 2014, British forces handed over the last bases in Helmand to the Afghan military, officially ending their combat operations in the war.