A major explosion shook central Baghdad Friday morning near an interior ministry building where U.S. troops found detainees showing signs of torture, witnesses said. There was no immediate information about casualties. The blast in the Jadiriyah neighborhood reverberated through the city center, sent a mushroom cloud hundreds of feet into the air and was followed by the sounds of sporadic small arms fire. The cause of the explosion was not immediately clear. Earlier this week U.S. troops found up to 173 malnourished detainees, some showing signs of torture, in the building. Most were believed to be Sunni Arabs, the main...