A car bomb exploded in a street lined with shops in the Iraqi city of Samarra on Saturday, Oct 12, killing at least 13 people, police and medics said.
A further 18 people were wounded in the blast in the city's al-Shurta district, Reuters reported.
A string of attacks across Iraq, including a coordinated wave of evening bombings in Baghdad, killed at least 45 people on Oct 7 as al Qaeda claimed responsibility for a recent spate of rare suicide attacks in the relatively peaceful Kurdish north.
Nearly 1,000 Iraqis were killed in September, one of the highest monthly death tolls in years, the UN said.
Iraq is going through its worst surge in violence since 2008, with near-daily militant attacks and relentless bombings blamed on hard-line Sunni insurgents. The surge followed a deadly crackdown by the Shiite-led government on a Sunni protest camp in northern Iraq in April. More than 5,000 people have been killed since then.
A statement from UNAMI said the mission recorded the deaths of 979 Iraqis in insurgent attacks in September. They included 887 civilians while the rest were members of security forces and Iraqi troops.
The figure was slightly lower than the UN's July death toll, which stood at 1,057, but still one of the highest in years.
The report said the worst-affected part was the Iraqi capital, Baghdad, where 418 people were killed in September. It said 2,133 people were wounded in last month's violence.