U.S. warplanes and attack helicopters opened fire on a group of suspected rebels in southern Afghanistan Sunday after the ambush of a coalition convoy, killing as many as 20 militants, the U.S. military said. The airstrikes occurred in southern Helmand province after rebels had pinned down coalition ground troops with rocket and small-arms fire, the military said in a statement. The fighting is the latest in a string of attacks and battlefield engagements across the south that have raised fears that Taliban rebels and their al-Qaida allies are regrouping. Full Story