Reporting from Baghdad — A double bombing Friday in the southern city of Karbala killed at least 32 people and wounded over 100 as hundreds of thousands of pilgrims commemorated a major Shiite Muslim holy day.

The attack took place at the eastern entrance to the city as pilgrims from around Iraq were leaving the commemorations in the city center. First a car bomb exploded near a hospitality tent erected to offer refreshments, killing 10 people, according to Karbala police. Moments later a suicide bomber driving a car plowed into the carnage left by the first explosion, and killed another 22.

It was the third major attack against pilgrims this week, and coincided with a sharp escalation in violence ahead of crucial national elections due in March. More than 70 pilgrims died in two other suicide bombings earlier this week as they headed for Kerbala to mark the Arbayeen, or 40th, day of mourning for Imam Hussein, the 7th century grandson of the prophet Mohammed.

Overall, there have been eight suicide bombings in Iraq the past 11 days, targeting hotels and government buildings as well as pilgrims, in a sign that the Sunni extremist insurgency appears to be regrouping in an attempt to destabilize the country ahead of the March 7 election.

U.S. officials blame Al Qaeda in Iraq for most suicide attacks, but the Iraqi government also accuses members of the former Baath Party that ruled Iraq under Saddam Hussein.

The start of the election campaign has been delayed by a dispute over whether hundreds of candidates with alleged ties to the Baath Party may participate, a dispute that has sharply escalated tensions between the ruling Shiite religious parties and the secular and Sunni groups who are hoping to unseat them.