1 0 , ▁the ▁already ▁complicated ▁relationship ▁with ▁Pakistan ▁( always ▁accused ▁by ▁the ▁US ▁of ▁hosting ▁the ▁Tal ib an ▁in ▁this ▁border ▁area ▁without ▁reporting ▁it ) ▁became ▁t ough er ▁after ▁the ▁NAT O ▁forces , ▁under ▁the ▁pre text ▁of ▁mit ig ating ▁the ▁Tal ib an ' s ▁power ▁over ▁this ▁area , ▁executed ▁an ▁attack ▁with ▁d ron es ▁over ▁the ▁Dur and ▁line , ▁passing ▁the ▁front ier ▁of ▁Afghan istan ▁and ▁killing ▁three ▁Pak ist ani ▁soldiers . ▁Pakistan ▁answered ▁by ▁closing ▁the ▁pass ▁on ▁ 3 0 ▁September ▁which ▁caused ▁a ▁con voy ▁of ▁several ▁NAT O ▁tr uck s ▁to ▁queue ▁at ▁the ▁closed ▁border . ▁This ▁con voy ▁was ▁attacked ▁by ▁extrem ists ▁apparently ▁linked ▁to ▁Al ▁Q a ida ▁which ▁caused ▁the ▁destruction ▁of ▁more ▁than ▁ 2 9 ▁oil ▁tank ers ▁and ▁tr uck s ▁and ▁the ▁killing ▁of ▁several ▁soldiers . ▁NAT O ▁chief ▁members ▁had ▁to ▁issue ▁a ▁formal ▁ap ology ▁to ▁the ▁Pak ist ani ▁government ▁so ▁the ▁supply ▁traffic ▁at ▁this ▁pass ▁could ▁be ▁restored . ▁ ▁In ▁August ▁ 2 0 1 1 , ▁the ▁activity ▁at ▁the ▁K hy ber ▁pass ▁was ▁again ▁halt ed ▁by ▁the ▁K hy ber ▁Agency ▁administration ▁due ▁to ▁the ▁more ▁possible ▁attacks ▁of ▁the ▁ins ur gency ▁over ▁the ▁NAT O ▁forces , ▁which ▁had ▁suffered ▁a ▁period ▁of ▁large ▁number ▁of ▁assault s ▁over ▁the ▁tr uck s ▁heading ▁to ▁supply ▁the ▁NAT O ▁and ▁IS AF