After the fall of Kabul to the Taliban, Ahmad Shah Massoud and Abdul Rashid Dostum formed the Northern Alliance, later joined by others, to resist the Taliban. Dostum's forces were defeated by the Taliban during the Battles of Mazar-i-Sharif in 1997 and 1998; Pakistan's Chief of Army Staff, Pervez Musharraf, began sending thousands of Pakistanis to help the Taliban defeat the Northern Alliance. By 2000 the Northern Alliance only controlled 10% of territory, cornered in the north-east. On 9 September 2001, Massoud was assassinated by two Arab suicide attackers in Panjshir Valley. Around 400,000 Afghans died in internal conflicts between 1990 and 2001.