Updated

The Taliban destroyed highway bridges southwest of Kabul during a wide-ranging assault on security forces, cutting off road traffic between the capital and three provinces for most of the day on Sunday, officials said.

Interior Ministry deputy spokesman Nasrat Rahimi said 14 police, including a district police chief, were killed as the insurgents tried but failed to capture the Sayed Abad district headquarters in the Maidan Wardak province. He said another seven security forces were wounded.

The highway between Kabul and Kandahar has since been reopened, and "the route has returned to normal," he added.

The insurgents burned down part of the district police headquarters and destroyed a number of checkpoints around the district, said Hekmat Durani, the provincial police chief's spokesman. Durani said that around 20 Taliban fighters were killed and wounded during the battle in Sayed Abad.

The Taliban said they overran the district headquarters, but local officials denied the claim.

Rahimi said reinforcements have been sent to the area and that the district is under the control of security forces.

The destruction of the bridges had cut off the main highway from Kabul to the Ghazni, Zabul and Kandahar provinces. The battle also cut off electricity to four provinces: Maidan Wardak, Logar, Ghazni and Paktia.

The Taliban have seized a number of districts across the country in recent years and regularly attack security forces. The latest assault comes just two weeks before Afghanistan holds parliamentary elections.

On Sunday, the U.N. mission in Afghanistan said civilian deaths from suicide bombings rose 46 percent in the first nine months of this year from the same period last year and that deaths from roadside bombs were up 21 percent. It says more than 1,000 people were killed and more than 2,500 have been wounded this year in both kinds of attacks, including scores of women and children.

It said suicide bombings caused more civilian deaths than any other form of violence, including ground battles between troops and insurgents.

"Deliberately targeting civilians is a war crime and cannot be tolerated," said Tadamichi Yamamoto, the U.N. envoy for Afghanistan. "The unpredictable nature of these types of attacks has caused Afghans unbearable suffering and forced them to live in fear of the next explosion, severely curtailing their ability to carry out normal lives."

The U.N. also documented a dramatic increase in attacks deliberately targeting civilians. While the Taliban mainly attack security forces and government officials, an Islamic State affiliate has launched a relentless wave of bombings targeting Afghanistan's Shiite minority.

The U.N. said that in the first nine months of this year it has documented more casualties from attacks on Shiites than in the whole of 2017.