BAGHDAD, Iraq - Eight suicide bombers struck in quick succession Saturday in a wave of attacks that killed 55 people as Iraqi Shiites marched and lash themselves with chains in ritual mourning of the death of the founder of their Muslim sect 14 centuries ago. Ninety-one people have been killed in violence in the past two days.

For the second year running, insurgent attacks shattered the commemoration of Ashoura, the holiest day of the Shiite religious calendar, but the violence produced a significantly smaller death toll than the 181 killed in twin bombings in Baghdad and the holy city of Karbala a year ago.