Islamic State militants attacked a checkpoint along the volatile Iraqi-Syria border on Monday, killing at least 15 Iraqi border policemen, officials said.

The attack took place in the town of al-Walid on Iraq's side of the border, according to a senior army official. At least five officers were also wounded in the assault. A government official in Iraq's Anbar provincial council confirmed the report but further details were not immediately available.

Since its blitz earlier this year, the Islamic State group has controlled most of the border crossings between Iraq and Syria. The Sunni militant group has also overrun a large part of Iraq's Anbar and Ninevah provinces and now controls about one-third of both Iraq and Syria.

The attack came as the U.N. Assistance Mission for Iraq said that 1,232 Iraqis were killed and 2,434 were wounded in violence and terror attacks in November. Of those killed, at least 296 were members of Iraqi and Kurdish forces, as well as militias who fight alongside them.

The figures are a slight decrease from October, when the U.N. said at least 1,273 Iraqis had been killed.

Also last month, at least 402 people were killed in western Anbar province, according to the provincial Health Directorate, the U.N. mission said. Most of the victims died in the provincial capital of Ramadi, a battleground between the IS group and Iraqi troops. In Baghdad province, at least 332 people were killed in November, the U.N. said.

On Monday, at least eight people died in the Shiite town of Balad, 50 miles north of Baghdad, after mortar shells hit a cluster of homes and a small market. Police officials said a woman and a child were among the dead and at least 20 people were wounded. Clashes are ongoing in Balad between Islamic State militants and Iraqi forces.

All officials spoke on condition of anonymity because they were not authorized to talk to media.