In one of the deadliest single attacks in postwar Baghdad, a truck bomb shattered a popular fruit-and-vegetable market in a teeming Shiite neighborhood Thursday, killing 67 people and wounding more than 150 others.

Militants from the self-described Islamic State claimed responsibility for the bombing that incinerated much of the Jameela market in the district of Sadr City. The dead and wounded were carried away in blood-soaked blankets and garbage bags amid the charred and twisted stalls and spilled produce.

The Sunni extremist group, which holds about a third of Iraq and neighboring Syria, said it targeted a gathering place for Shiites and vowed more attacks. It often attacks military checkpoints or predominantly Shiite areas with the goal of undermining confidence in the government's security efforts.

When it launched its major onslaught across northern Iraq last year, the Islamic State group vowed to continue on to Baghdad, but a mobilization of volunteer Shiite fighters deterred any significant attacks on the capital at that time.

For the past two weeks, thousands of Iraqis have staged protests calling on the government to take a firm stance against corruption and reckless spending. Many see the corruption in the security forces as a major cause for its failures.

This week, the government approved a reform plan by Prime Minister Haider al-Abadi that includes taking some money that was to go to individual officials and redirecting it to strengthening the Interior and Defense ministries.

While attacks are common in Baghdad, Thursday's was the deadliest single bombing in the capital since the height of Iraq's sectarian bloodletting in 2006-07. More than 200 people were killed in a 2006 attack by a series of car bombs and mortar rounds that struck Sadr City. That prompted the government to implement a 24-hour curfew in Baghdad that remained in effect, on-and-off, until earlier this year, when al-Abadi lifted it to try to return some semblance of normal life in the capital.

In another major attack in Sadr City in 2013, two suicide bombers hit a cluster of funeral tents packed with mourning families, killing 72 people. Another 20 people were killed elsewhere in Iraq that day.

In Thursday's attack, police said the attackers put the explosives in a refrigeration truck so that it fit in with other vehicles delivering supplies to the market, the main center for produce and food sales in Baghdad. The bomb was detonated shortly after dawn.

Hassan Hamid said he was driving his minibus near the area when the force of the blast threw his vehicle about 10 meters (30 feet) away and onto the sidewalk.

"This is the strongest explosion I've ever seen in my life," said the 37-year-old father of three, speaking from his hospital bed where he was treated for shrapnel wounds. "I saw some cars were thrown into the sky and a fire erupted all over the place."

Ambulances and private cars ferried the wounded to hospitals. Long after the explosion, emergency vehicles remained at the scene, where firefighters doused the smoldering ruins.

Two police officers and four hospital officials confirmed the casualty figures of 67 dead and 152 wounded. All spoke on condition of anonymity because they were not authorized to talk to the media.

The market is especially crowded on Thursdays because shoppers from other provinces stock up on food for the weekend, one of the officers said.

In a message posted on an IS-affiliated Twitter account, the Islamic State said it detonated the truck bomb in order to have the "rejectionists (Shiites) experience the same harm as their bombardments cause to our Muslim people." The Sunni militant group, which seeks to establish a "caliphate" in Iraq and Syria, views Shiite Muslims, as well as other religious minorities, as apostates.

Parliament's security committee denounced the bombing, saying it "shows the ugliness and brutality" of the attackers.

Shiite lawmaker Hakim al-Zamili, who heads the committee, reiterated demands for a security review and for improving Iraq's intelligence services.

Al-Zamili also urged forming neighborhood groups that would keep Iraqi forces updated on the local situation, and he called for the firing of security officials whose failures may have led to the Sadr City attack, saying this was their "last warning."

Gyorgy Busztin, the acting chief of the U.N. mission in Iraq, called Thursday's attack "heinous and cowardly."

French President Francois Hollande also condemned the attack and said he spoke with al-Abadi by telephone to express his support.

Sadr City, previously known as Saddam City before the 2003 U.S.-led invasion, is home to some 3 million, with most of them Shiite Muslims. The district saw some of the worst fighting in the early days of the war. In 2004, coalition troops engaged in bloody battles in Sadr City and elsewhere with members of the Mahdi Army — fighters loyal to radical Shiite cleric Muqtada al-Sadr.

The Islamic State group claimed responsibility for a suicide car bombing Monday at a marketplace in Baquba, the capital of eastern Diyala province, that killed 34. The militants also targeted a market in Diyala last month, killing more than 115 people in one of the worst-single attacks to tear through the country in a decade.

The Iraqi military launched a large-scale operation last month to retake the western province of Anbar from the extremists.

A U.S.-led coalition has been bolstering Iraqi troops in their efforts to claw back territory from the militants for the past year. But while security forces successfully managed to recapture Saddam Hussein's hometown of Tikrit in April, operations elsewhere have stalled as government-backed forces struggle to dislodge the extremists from Iraq's biggest Sunni strongholds.

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Associated Press writer Murtada Faraj in Baghdad contributed to this report.