In July 2003, Pakistani and Afghan forces clashed over border posts. The Afghan government claimed that Pakistani military established bases up to 600 meters inside Afghanistan in the Yaqubi area near bordering Mohmand Agency. The Yaqubi and Yaqubi Kandao (Pass) area were later found to fall within Afghanistan. In 2007, Pakistan erected fences and posts a few hundred metres inside Afghanistan, near the border-straddling bazaar of Angoor Ada in South Waziristan, but the Afghan National Army quickly removed them and began shelling Pakistani positions. Leaders in Pakistan said the fencing was a way to prevent Taliban militants from crossing over between the two nations but Afghan President Hamid Karzai believed that it is Islamabad's plan to permanently separate the Pashtun tribes. Special Forces from the United States Army have been based at Shkin, Afghanistan, seven kilometres west of Angoor Ada, since 2002. In 2009, the International Security Assistance Force (ISAF) and American CIA have begun using unmanned aerial vehicles from the Afghan side to hit terrorist targets on the Pakistani side of the Durand Line.