Deaths in the capital Kabul accounted for nearly 20 percent of the toll, according to the report by the UN Assistance Mission in Afghanistan (UNAMA), which has been documenting civilian casualties in the war-torn country since 2009.
The majority of the victims were killed by anti-government forces -- including the Taliban and in attacks claimed by the Islamic State, the report said.
The first six months of the year has seen a significant rise in the number of civilian lives lost in highly coordinated attacks involving more than one perpetrator, with 259 killed and 892 injured - a 15% increase on the same period last year.
Many of those deaths happened in a single attack in Kabul in late May when a truck bomb exploded during the morning rush hour, killing more than 150 people and injuring hundreds. UNAMA put the civilian death toll at 92, saying it was the deadliest incident to hit the country since 2001.
Women and children affected the most
The UN's special envoy to Afghanistan Tadamichi Yamamoto said the human cost of the conflict remains "far too high".
"The continued use of indiscriminate, disproportionate and illegal improvised explosive devices is particularly appalling and must immediately stop," he added in a statement.
Women and children have borne the brunt of the increase in civilian casualties, with UNAMA blaming the use of IEDs and aerial operations in populated areas for the jump.
A total of 174 women were killed and 462 injured - an overall rise in casualties of 23% on last year - while 436 children were killed in the same period, representing a 9% increase.
Nearly half of Afghanistan's 34 provinces have seen an increase in civilian deaths in the first six months of the year, mainly due to the rise in attacks by anti-government forces.
The ground offensives by Afghan security forces are the second leading cause of civilian casualties, though UNAMA said there had been a 10% decrease compared to the same period in 2016.
According to the UN's figures, more than 26 500 civilians have died and nearly 49 000 injured as a result of armed conflict in Afghanistan since January 2009.