Shi'ite militia forces executed 15 Sunni Muslims and then hung them by electricity poles in a public square in a town northeast of Baghdad today, police said.

A police officer at the scene in Baquba, a mixed Sunni and Shi'ite town 65 km (40 miles) from Baghdad, said he believed the action was designed to keep Sunnis from supporting the Islamic State, an al-Qaeda offshoot which seized swathes of land in an advance through northern Iraq last month.

The victims, who were kidnapped over the last week, were shot in their heads and chests and then hung up by cables.

"The militia forces are preventing the medical crew from bringing down the bodies hanging from the electricity poles," he told Reuters.

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

In other violence on Wednesday, a car bomb exploded near restaurants and shops, killing 10 people, police said.

The U.S.-funded and trained Iraqi army unraveled in the face of the Islamic State's sweep through the north and sectarina violence has increased since then. Islamic State allies had already taken control of parts of western Iraq.

Shi'ite militias, seen as a vital line of defence, stepped in to challenge the Sunni insurgents after Iraq's top cleric called on his compatriots to take up arms against the Islamic State.

Prime Minister Nuri al-Maliki, a Shi'ite, promised in his weekly speech to the nation on Wednesday to end the Islamic State menace to Iraq, an OPEC member.

But critics say Maliki's authoritarian and sectarian rule have alienated Sunnis, prompting some to find common cause with the group, which has blown up Shi'ite shrines and mosques.

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