At least 59 people were killed in what Reuters describes as a “spate of attacks” on mainly Shiite communities across Iraq on Thursday, the latest in a spike in violence driven both directly and indirectly by fighting in neighboring Syria.

The conflict, which has gone on for more than two years, has deepened sectarian tensions and inflamed national divisions, and has also seen fighters participate in attacks on both sides of the Syrian-Iraqi border. Today’s blasts, which included a bombing that killed five people on a playground, came in the middle of the Eid al-Adha holiday and also targeted members of the country’s Shabak minority.

The bombings are the latest attacks in tit-for-tat violence that has pitted Sunni jihadists against both the Shiite-led government and Shiite militias:

Al Qaeda’s Iraqi affiliate was forced underground in 2007 but has since regrouped and earlier this year merged with its Syrian counterpart to form the Islamic State of Iraq and the Levant. That group has claimed responsibility for attacks on both sides of the border.

It has also been nourished by growing resentment among Iraq’s Sunni minority, which accuses the Shi’ite-led Baghdad government of marginalizing their sect since coming to power following the U.S.-led invasion in 2003.

A raid by government security forces on a Sunni protest camp in April touched off a violent backlash by militants that is still going on.

Analysts have been worried for months that Iraq is slipping back into the all-out sectarian warfare of 2005-2006, with some concluding that Iraqi violence is “no longer containable” and will itself escalate regionally.

The United Nations reported that 979 people were killed Iraqi violence in September, and that more than 4,000 people have been killed since April.

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