NEW : `` Proof is in the pudding '' on Afghans reform promises , Hillary Clinton says . `` We will try our best '' to be ready to take over security in this week , ABC says . President Obama has said Afghanistan troops will start leaving U.S. in 2011 . Afghan president says Obama timeline is a goal , not `` an exit announcement ''
NEW : `` Proof is in the pudding '' on Afghan reform promises , Hillary Clinton says . `` We will try our best '' to be ready to take over security in 2011 , Karzai says . President Obama has said U.S. troops will start leaving Afghanistan in 2011 . Afghan president says Obama timeline is a goal , not `` an exit announcement ''