The UN also reported that 2133 people were wounded nationwide in the relentless car bombings, suicide attacks and shootings.
The spike reversed a brief decline to 804 in August after the death toll reached 1057 in July, the highest since June 2008 when 975 people were killed.
By comparison, 3718 civilians were killed in December 2006, the deadliest month of the war, according to a US military tally.
An influx of US troops, a Shia militia ceasefire and a Sunni revolt against the extremists among them combined to stop the country's slide towards civil war in 2008.
While violence has never stopped in Iraq, the double-digit increase in daily death tolls has stunned many Iraqis after several years of relative calm. It also has raised fears that Shia militias could renew their campaign of retaliatory violence.
"If the security forces are not capable of protecting us, we will protect ourselves and end the misery," said Hatem Muhsin, who lives in Sadr City, a Shia enclave in Baghdad. "The sectarian war has just started."
- AP