Iraqi security forces found 53 corpses, blindfolded and handcuffed, south of Baghdad on Wednesday as Shi'ite and Kurdish leaders traded accusations over an Islamist insurgency raging in the country's Sunni provinces, according to The Associated Press.

Officials said dozens of bodies were discovered near the mainly Shi'ite Muslim village of Khamissiya, with bullets to the chest and head, the latest mass killing since Sunni insurgents swept through northern Iraq, the AP reported.

"Fifty-three unidentified corpses were found, all of them blindfolded and handcuffed," Sadeq Madloul, governor of the mainly Shi'ite southern province of Babil, told reporters, according to the AP.

Madloul said the victims appeared to have been killed overnight after being brought by car to an area near the main highway running from Baghdad to the southern provinces, about 15 miles southeast of the city of Hilla, the AP reported. The identity and sectarian affiliation of the dead people was not immediately clear, he said.

Sunni militants have been carrying out attacks around the southern rim of Baghdad since spring, and in response, Shi'ite militias have been active in rural districts of Baghdad, abducting Sunnis they suspect of terrorism, many of whom later turn up dead, according to the AP.

Mass killings of scores of victims have become a regular occurrence in Iraq for the first time since the worst days of sectarian and ethnic cleansing in 2006-2007, the AP reported.

The Sunni insurgents, led by the group known as the Islamic State which considers all Shi'ites heretics who must repent or die, boasted of killing hundreds of captive Shi'ite army troops after capturing the city of Tikrit on June 12, according to the AP. They put footage on the Internet of their fighters shooting prisoners.

Amnesty International and the United Nations have reported several other suspected incidents of mass killings of prisoners in government custody, the AP reported.

The fighting between the Islamic State, formerly known as the Islamic State in Iraq and the Levant, backed by other armed Sunni groups, and the army backed by Shi'ite militias, threatens to split the country, according to the AP.

The renewed sectarian war has brought violence to levels unseen since the very worst few months of the fighting that followed the U.S. invasion to topple Saddam Hussein in 2003, the AP reported. Abductions have also increased.