Three separate attacks in Iraq left at least 36 dead on Wednesday, police told Reuters. In the most gruesome of the three attacks, Shiite militia forces executed 15 Sunni Muslims and then hung them from electricity poles in a public square.

A car bomb exploded in Baghdad’s Shiite district of Sadr City killing 16 people. A second car bomb exploded in Baghdad, this one near the Ameen district, killing five, police told Reuters.

According to Baghdad police, the victims were kidnapped last week before they were executed. They were found with gunshot wounds to the head and chest.

"They are following a new tactic of keeping bodies hanging for a longer time to deter the Sunni population from backing the Islamic State,” police told Reuters. “We asked them to let us evacuate the bodies but they refused."

Violence has been increasing in Iraq since the Sunni-extremist insurgents, the Islamic State, formerly known as the Islamic State of Iraq and Syria, took over Mosul, Iraq’s second largest city in June. It has been threatening to take over the capital, threatening to push the country into a sectarian civil war akin to the one that plagued the country in 2007.

In Iraq, Shiites have been the U.S.-imposed ruling sect since Nouri al-Maliki, the former Shiite dissident under the rule of Baathist Saddam Hussein, was elected prime minister. Police forces and the army are, in theory, aligned with Shiite militia responsible for Wednesday’s attacks, but infiltrations are common even though Maliki purged many of the non-Shiite members. s