At least 20 people in a crowd of Shi'ite pilgrims have been killed in a bomb attack in Iraq's holy city of Kerbala. More than 100 people were injured.

The bomb was on cart pulled by a motorcycle which ploughed into a mass of people. Hundreds of thousands of pilgrims from various Arab states have gathered in Kerbala for Arbain - which marks 40 days of mourning for Hussein, the Prophet Mohammed's grandson. Most of the victims had come to the city especially for the holy day. The attack is seen as an attempt by al-Qaeda to increase sectarian tensions between Shi'ite and Sunni Muslims.

On Monday a suicide bomber blew herself up among Shi'ite pilgrims on the outskirts of the Iraqi capital Baghdad, killing 40 people. Monday's attack took place at a gathering point for people setting off on the Arbain pilgrimage to Kerbala.

Mosque in Kerbala, today's bomb leaves 20 dead. Photo The Poss, on Flickr.com