"The human cost of this ugly war in Afghanistan - loss of life, destruction and huge suffering - is too far too high", said the UN Secretary-General's Special Representative for Afghanistan and head of UNAMA, Tadamichi Yamamoto.
The first six months of the year have 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 percent increase on the same period last year. These deaths and injuries represent 67 percent of the total civilian casualties, with 43 percent attributed to the Taliban, 5 percent to Daesh in the Khorasan province, and the rest to unidentified attackers.
The majority of the victims were killed by anti-government forces - including the resurgent Taliban and in attacks claimed by the Islamic State, the report said, underscoring spiralling insecurity in the country almost 16 years after the U.S. invasion.
The report commended government forces for reducing civilian casualties from ground engagements.
The report concludes with recommendations to the Government of Afghanistan, anti-government groups and global military forces offering aid to "support their efforts to protect civilians, prevent civilian casualties and uphold their obligations under worldwide humanitarian and human rights law".
The study by the group cited unawareness about war areas, firefighting in crowded and populated areas, lack of mine-clearing progammes in recaptured areas, mistaken strikes by foreign and national forces, bombardment of civilian houses as reasons behind the increased civilian deaths.
"The Islamic Emirate is much more sensitive to and vigilant about prevention of civilian casualties than any other side", he added, using the official name of the Taliban.
FORECAST: Storm chances shrink as heat builds this week
Unless models start trending a little cooler, we'll likely have to contend with heat-related headlines by the end of the week. Will monitor this trend throughout the week but it makes more sense for Sunday night rain and not Saturday night .
Deaths in the capital, Kabul, which has historically been one of the safest places in Afghanistan, accounted for some 20 percent of the total tally.
The reports highlights that 40 per cent of all civilian casualties during the six-month period were killed or injured by anti-government forces using improvised explosive devices (IEDs), such as suicide bombs and pressure-plate devices, which were responsible for the deaths of 596 civilians and injured 1,483.
The investigators praised US-backed Afghan police and soldiers, with civilian casualties caused by them 21 percent lower this year. "Many more have been forced from their homes and suffered lasting damage to their health, education and livelihoods", Zeid Ra'ad Al Hussein, the U.N. High Commissioner for Human Rights, said in a statement accompanying the report.
Defense Secretary James Mattis has promised to have a new strategy for Afghanistan ready this month.
He said the strategy is still being worked on, particularly the State Department's contributions. That strategy is expected to include sending a few thousand more US troops to the country.
"Welcome to strategy", Mattis said when asked about the delay. "I don't know where to find them". "This is hard work, and anyone who says otherwise is someone who has not had to either deal with it, or deal with the consequences of the decisions they made".