Israeli troops raided the West Bank city of Nablus before dawn Tuesday, and two Palestinians were shot and killed in the ensuing violence, Palestinian witnesses and doctors said. Troops patrolled the Old City, taking up points on roofs and detaining at least five suspected fighters, the witnesses said. At least two exchanges of fire broke out, and three gunmen from the Al Aqsa Martyrs' Brigades militia were injured, two seriously, the group said. One, a local leader of the group, later died of his wounds. doctors said. A Palestinian man, 70, was shot just as he left his house in the area and later died of his wounds, his family and doctors said. It was not immediately clear if there was an exchange of fire at the time, the Associated Press reported. Residents frightened by the shooting stayed in their homes even as day broke.