Rising violence ahead of Afghanistan’s disputed presidential election made August the deadliest month of the year for civilians, the U.N. said, warning in a new report that attacks could spike again when the final vote results are announced.

A total of 1,500 civilians died in Afghanistan from January through August, according to the report released late Friday. About three-quarters of the deaths were blamed on militants. The U.N. report did not specify the August death toll, but said the month was the deadliest of the year as the Taliban stepped up an intimidation campaign to discourage Afghans from voting in the Aug. 20 election.

The U.N. said coalition forces were to blame for about a quarter of civilian deaths in 2009 — most of them in airstrikes. The top NATO commander, U.S. Gen. Stanley McChrystal, has made protecting Afghan civilians a top priority.

An Associated Press count found a total of 174 civilians were killed in August, 165 of them at the hands of militants. The deadliest attack of the month was an Aug. 25 truck bomb in the southern city of Kandahar that killed 43 people.

“In terms of the numbers of security incidents we saw, this represented a new high,” said Adrian Edwards, the U.N. spokesman in Afghanistan.

This has already been the deadliest year of the war for U.S. and NATO forces and the numbers released Friday indicate that ordinary Afghans have not been spared. The U.N. recorded 1,145 civilian deaths in the first eight months of last year and a record 2,118 for all of 2008.

Since then, the Taliban have extended their grip on vast parts of the country, including areas that had been relatively peaceful in the years since the 2001 U.S. invasion to oust the hard-line group from power for sheltering Osama bin Laden and other al-Qaida leaders.

Bombs and suicide attacks accounted for 39.5 percent of civilian deaths this year, the U.N. said, warning there are “fears of a return to violence when election results are announced.”

Preliminary results from the election show President Hamid Karzai with 54.6 percent, but a U.N.-backed complaints commission is now throwing out tainted ballots. If enough are found to be fraudulent, Karzai could dip below the 50 percent threshold needed to avoid a runoff with his top challenger.

Afghan election officials involved in a recount are racing to meet a narrowing window for a possible runoff before winter.

In the country’s latest violence, 18 Taliban militants were killed in a battle after they attacked a government building early Saturday in the Dushti Archi district of northern Kunduz province, Gov. Mohammad Omar said. None of the Afghan army soldiers or police officers that responded to the attack was killed, he said.

Kunduz, in the country’s far north, is one of the regions that had been peaceful in past years but has seen an influx of militants in 2009.