According to the report, the suicide attacks had attributed to 40 percent of the civilians casualties in 2017.
Two-thirds of all casualties a year ago were inflicted by anti-government forces, with the Taliban responsible for 42 percent, Islamic State 10 percent and 13 percent caused by undetermined anti-government elements.
"The chilling statistics in this report provide credible data about the war's impact, but the figures alone can not capture the appalling human suffering inflicted on ordinary people, especially women and children", Tadamichi Yamamoto, the secretary-general's special representative for Afghanistan, said in a statement.
Danielle Bell, director of human rights of the United Nations Assistance Mission in Afghanistan, speaking Thursday described the nine percent reduction in civilian casualties a year ago as an "important step" towards minimizing harm to non-combatant Afghans.
"UNAMA documented 631 civilian casualties (295 deaths and 336 injured) from aerial operations conducted by pro-government forces, a seven per cent increase from 2016, and the highest number from airstrikes in a single year since 2009", the press release said. "The people of Afghanistan, year after year, continue to live in insecurity and fear, while those responsible for ending lives and blighting lives escape punishment", said UN High Commissioner for Human Rights Zeid Ra'ad Al Hussein.
In their statement, the Taliban did not mention a January 27 raid on a top Kabul hotel, in which more than 30 people were killed, nor a bomb attack on a crowded street a week later that killed more than 100. Such attacks killed 202 people and injured another 297 during 38 attacks last year, or about three times as many as during the previous year. They claimed both attacks.
The air campaign by worldwide and government forces accounted for 6 percent of civilian casualties in 2017, with 295 people killed and 336 wounded, a 7 percent increase over the previous year.
"It has indeed been a hard year".
It attributes 16 per cent to Afghan forces and 2 per cent to worldwide forces, with the rest remaining unclear.
Women and children remained heavily affected by conflict-related violence. Child casualties - 861 killed and 2,318 injured - decreased by 10 per cent compared with 2016.
"We can not sleep day and night due to the frightening sounds of firing", an 11-year-old girl injured by a bullet during a ground engagement in Arghandab district, Zabul province in September, told UNAMA.
Airstrikes by Afghan and United States forces, which increased by seven per cent, killed 295 people and wounded 336 others, making up six per cent of the overall casualty figures.