(CBS) A U.S. Army Black Hawk helicopter was shot down in southern Iraq Wednesday, killing seven of the 11 soldiers aboard, Pentagon officials said. The helicopter was downed by small-arms fire near Karbala, the site of fierce fighting between the Army's 3rd Infantry Division and Iraqi troops, including Republican Guard forces. Four other soldiers on board the Black Hawk were wounded, but rescued by American troops, the officials said. The Black Hawk was the second U.S. helicopter to go down in combat. An Army Apache assault helicopter went down March 24 during an assault on Republican Guard forces; its two pilots...