More than 1,000 people were killed in violence in Iraq during May, making it the deadliest month since the height of sectarian bloodletting in 2006-07.

The vast majority of casualties in June were civilian, with 131 policemen and 76 members of the Iraqi security forces also killed, the United Nations said in a statement.

The worst-affected region was Baghdad, where 258 people were killed and the death toll in Salahuddin, Diyala, Nineveh and Anbar provinces each exceeded 100, the statement said.

On Monday, police discovered the bodies of eight former members of a government-backed Sunni militia who had been killed execution-style and dumped near the town Tarmiya, 25 km (15 miles) north of the capital.

Sectarian tensions in Iraq and the wider region have been inflamed by the civil war in Syria, where mainly foreign backed terrorist groups are fighting to overthrow President Bashar al-Assad.

Last year, a total of 4,471 civilians were killed.