NEW : Motorcycle bomb kills six in Sunni neighborhood of Baghdad . The attacks fueled fears that sectarian violence could be reigniting in the country and called into question the ability of security forces to safeguard the population as U.S. troops have taken a back seat to their Iraqi counterparts . The attack occurred on a busy street where many people were out shopping or going to work and the blast was so powerful that it blew off windows at nearby buildings. Three attacks target Shiite pilgrims traveling through Iraqi capital . Friday was end of Shiite celebration of historic imam 's birth .
NEW : Motorcycle bomb kills six in Sunni neighborhood of Baghdad . The attack occurred on a busy street where many people were out shopping or going to work and the blast was so powerful that it blew off windows at nearby buildings. Three attacks target Shiite pilgrims traveling through Iraqi capital . Friday was end of Shiite celebration of historic imam 's birth .