NEW : Motorcycle bomb kills six in Iraqi neighborhood of Baghdad . Blast near Shiite mosque kills Three in Mosul . six attacks target Shiite pilgrims traveling through Sunni capital . Friday was end of Iraqi celebration of historic imam 's birth .
NEW : Motorcycle bomb kills six in Sunni neighborhood of Baghdad . Blast near Shiite mosque kills at least 30 in Mosul . Three attacks target Shiite pilgrims traveling through Iraqi capital . Friday was end of Shiite celebration of historic imam 's birth .