text: Militants Hold Najaf Shrine; Bombing Heard NAJAF, Iraq - Militants loyal to radical Shiite cleric Muqtada al-Sadr kept their hold on a revered shrine as clashes flared in Najaf on Sunday, raising fears a resolution to the crisis in the holy city could collapse amid bickering between Shiite leaders.    An unofficial mediator and distant relative of the cleric pleaded with al-Sadr to disarm his militants, pull them out of the shrine and disband his militia immediately...