U.S. aircraft launched a fresh assault on Shi'ite rebels in the embattled Iraqi city of Najaf early Sunday after talks on transferring control of the mosque at the center of a two-week siege ran into trouble. A U.S. military AC-130 gunship unleashed rapid cannon and howitzer fire on positions held by rebels loyal to radical cleric Moqtada al-Sadr, a Reuters witness said. The attack lit the area with white flashes and was followed by a blast. Smoke drifted over the old city near rebel positions, and flashes were seen on the outskirts of the city. Tracer fire and orange flashes...