Iraqi security forces inspect the site of a car bomb attack in Basra, Iraq, on Sunday. (Nabil al-Jurani/AP)

Car bombings and other attacks in Iraq killed at least 53 people Sunday in mostly Shiite-majority cities, another bloody reminder of the government’s failure to stem the surge of violence that is feeding sectarian tensions.

Iraq is experiencing its deadliest bout of violence since 2008, raising fears that the country is returning to the kind of widespread killing that pushed it to the brink of civil war in the years after the 2003 U.S.-led invasion. More than 4,000 people have been killed in attacks since the start of April, including 804 in August, according to figures from the United Nations.

The deadliest attack Sunday was in Hillah, a city 60 miles south of Baghdad, where a car bomb near an outdoor market killed nine civilians and wounded 15, a police officer said. A little later, another car bomb went off nearby, killing six civilians and wounding 14, he said.

In the nearby town of Iskandariyah, a car bomb exploded in a parking lot, killing four civilians and wounding nine, police said.

Another car bomb went off in an industrial area of the Shiite city of Karbala, killing five and wounding 25, a police officer said. Karbala is about 60 miles southwest of Baghdad. In the aftermath, security officials inspected burned-out cars in front of what appeared to be a row of smashed workshops.

In Kut, a Shiite-dominated city 100 miles southeast of Baghdad, a car bomb targeted construction workers and food stalls, killing two and wounding 14, a provincial police officer said.

Seven more civilians were killed and 31 were wounded when four car bombs ripped through the towns of Suwayrah and Hafriyah outside Kut, police said.

In Baghdad’s Sunni-dominated Adhamiyah neighborhood to the north, a car bomb that exploded near the convoy of the head of Baghdad’s provincial council killed three and wounded eight, police say. The council head escaped unharmed.

Two other car bombs hit the southern cities of Basra and Nasiriyah, killing eight civilians and wounding 26, two police officers said. And two civilians were killed when a bomb hit a police patrol in Baghdad’s Sunni suburb of Abu Ghraib to the west.

To the northeast of Baghdad, gunmen broke into a farm in the village of Abu Sayda and killed three Sunni farmers, police said.

On Sunday afternoon, police found the bodies of four Sunni men who had gunshot wounds to the head. The men, all relatives, were kidnapped earlier in the day by gunmen who stormed their house in Baghdad’s Yusufiyah suburb.

No one has asserted responsibility for the blasts, which targeted commercial areas and parking lots in seven cities. But systematically organized waves of bombings are a hallmark of al-Qaeda’s local branch, known as the Islamic State of Iraq and the Levant.

— Associated Press