WASHINGTON -- The top U.S. commander in Afghanistan says passage of a House resolution calling for withdrawal of American forces by year's end would undermine the coalition effort and be hailed by the Taliban and Al Qaeda as a victory.

Army Gen. David Petraeus told Congress this week that the war is turning around and the United States is on track to begin drawing down troops in July. The timeline calls for ending U.S. and NATO combat operations by the end of 2014.

But supporters of the House resolution say that's not fast enough. The resolution calls for the president to withdraw U.S. forces no later than Dec. 31 of this year. The measure has failed in the past and is almost certain to fail again Thursday.