Two suicide bombers detonated vehicles packed with explosives on the outskirts of the holy Shiite shrine city of Karbala on Thursday killing at least 45 people. A top official said in Baghdad that at least 150 others were wounded in the twin attacks, which occurred about 20 minutes apart at separate entrances to the city, 110 kilometres south of Baghdad.More than a million pilgrims are expected to visit Karbala in the coming days for ceremonies to commemorate Arbaeen, which marks 40 days since the anniversary of the death of the revered 7th century Imam Hussein. The attack comes amid a spike in violence in Iraq, which had been relatively calm after Prime Minister Nuri al-Maliki formed a new government in December, more than nine months after parliamentary elections.