BAGHDAD -- The death toll from a car bombing south of Baghdad claimed by the Islamic State group rose to 73 on Friday, including about 40 Iranian pilgrims, Iraqi hospital and police officials said.
They said 65 other people were wounded in the attack, which took place on Thursday night at a gas station on a major highway near the city of Hilla, about 60 miles south of the Iraqi capital.
Earlier, the officials had put the death toll at 56. The officials spoke on condition of anonymity because they were not authorized to talk to the media.
IS claimed the attack in a brief statement on its Aamaq media arm, saying it was a suicide truck bomb.
The attack appears to have targeted a bus with Iranian pilgrims heading home after a major Shiite religious observance in the holy city of Karbala.
Iran's Deputy Foreign Minister Hassan Qashqavi was quoted by the semi-official Tasnim news agency on Thursday night as saying that 80 people were killed, including 40 Iranians. Conflicting death tolls are common in the aftermath of large attacks.
The attack was the deadliest by IS since a massive car bomb killed around 300 people in Baghdad in July. It also came a day after some dozen small-scale bombings in and around Baghdad killed 31 people and wounded more than a 100 -- a particularly bloody day even by the standards of the Iraqi capital, which has for more than a decade endured near-daily violence blamed on IS or its forerunner, al-Qaida in Iraq, and which mostly targeted members of Iraq's Shiite majority.
The gas station bombing underlined the continuing ability of IS to stage high-profile terror attacks even as a massive Iraqi military operation is underway to dislodge its fighters from its last major urban stronghold in Iraq, the northern city of Mosul. The offensive is aided by volunteer militiamen and the U.S.-led coalition, which has mostly been pounding IS targets in Mosul with airstrikes.
Moreover, Thursday's IS bombing took place in Iraq's Shiite hinterland south of Baghdad, a region that has largely been spared the near-daily violence that has for years engulfed the capital and Sunni regions.
Earlier this week, Prime Minister Haider al-Abadi visited Karbala, where he lavishly praised the country's security forces for protecting the pilgrims against attacks by IS.
Extremist Sunni militants, including the Islamic State group, view Shiites as heretics and routinely target Iranian pilgrims who visit Iraq by the hundreds of thousands to pay homage to major Shiite shrines in Baghdad, and also the Shiite holy cities of Karbala and Najaf, south of Baghdad, and Samarra, to the north of the capital.
The Shiite observance in Karbala, called the al-Arbaeen, in which the Iranian victims participated was the 40th day after the death anniversary of a much revered, 7th-century religious figure, Imam Hussein, the grandson of the Prophet Muhammad. The ceremonies routinely attract hundreds of thousands of pilgrims, including many Iranians who travel overland into Iraq for the occasion.
The Iraqi government campaign to retake Mosul began last month, but stiff IS resistance and concerns over the safety of civilians who remain inside the city have slowed the Iraqi forces' progress.
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