Bombs targeting protesters and pilgrims outside Baghdad killed 14 people on Tuesday, the latest in a surge of violence that has sparked fears of a revival of all-out sectarian conflict.

The latest attacks came a day after 35 people were killed nationwide, most of them in a wave of car bombings in the capital, as Iraq grapples with a prolonged political deadlock and months of protests among its Sunni Arab minority.

No group immediately claimed responsibility for the attacks, which pushed the overall death toll for June above 350.

But Sunni militants linked to Al-Qaeda frequently target Shiite Muslims -- both the protesters and the pilgrims were from Iraq's Shiite majority -- whom they regard as apostates.

Tuesday's deadliest attack struck the ethnically-mixed town of Tuz Khurmatu, which lies in a tract of territory in the north that Kurdistan wants to incorporate into its three-province autonomous region over Baghdad's objections.

Two suicide bombers blew themselves up inside a tent packed with Shiite Turkmen protesters in the town, killing at least 11 people and wounding 55, the town's interim mayor and a doctor said.

Among the dead were a former deputy provincial governor and his two sons, as well as a former provincial councillor.

The protesters had been rallying over poor security in the town, which is regularly hit with attacks.

"Today is the worst day of my life -- no one remains from my friends and relatives," said Hassan al-Bayati, who suffered wounds to an arm and a leg, speaking from his hospital bed.

Referring to the heavy security presence in the town, Bayati continued: "I ask our political leaders -- what is the value of the thousands of army and peshmerga (Kurdish security forces) who cannot protect Tuz, even though they are deployed everywhere?"

The unresolved dispute over the territory, which stretches from Iraq's eastern border with Iran to its western frontier with Syria, is cited by diplomats as one of the biggest threats to the country's long-term stability.

Analysts often voice worry that the tensions could spill over into open conflict between central government forces and Kurdish troops.

Also on Tuesday, a magnetic "sticky bomb" attached to a minibus went off as Shiite pilgrims were on their way to the central shrine city of Karbala for Shabaniyah commemorations, which mark the anniversary of the birth of Imam Mehdi, the so-called 12th imam and a key figure in their faith.

Three people were killed and 15 wounded when the bomb went off near the town of Iskandiriyah, police and a doctor said.

In east Baghdad, gunmen wounded two guards outside an Assyrian church.

Tuesday's attacks struck a day after a wave of car bombs across the Iraqi capital and unrest north of Baghdad killed 35 people, with the country struggling with a prolonged political deadlock and violence at its worst levels since 2008.

Attacks have increased markedly since the beginning of the year, coinciding with rising discontent among the Sunni Arab minority that erupted into protests in late December.

Analysts say a failure by the Shiite-led authorities to address the underlying causes of the demonstrations has given militant groups both a recruitment platform and room to manoeuvre.