During the first three months of 2019, global and pro-government forces were responsible for the deaths of 305 civilians, whereas insurgent groups killed 227 people, the United Nations Assistance Mission in Afghanistan (UNAMA) said in a quarterly report.
USA air strikes killed 140 civilians, while Afghan government strikes killed 5.
The report documented four suicide attacks by militants during the first three months of the year that killed or wounded 178 civilians.
The report says that During the first three months of 2019, Anti-Government Elements remained responsible for the majority of civilian casualties, causing 963 civilian casualties (227 deaths and 736 injured), representing a 36 per cent decrease as compared to the same time period in 2018.
Women and children made up half of the civilian casualties from aerial operations, it stated.
"It is unclear whether the decrease in civilian casualties was influenced by any measures taken by parties to the conflict to better protect civilians, or by the ongoing talks between parties to the conflict", the report said.
The UNAMA report said a total of 145 civilians were killed during the first three months of 2019 by USA and Afghan government air strikes.
The U.S. military regularly disputes UNAMA's figures.
"Every death, every injury is a tragedy for civilians", said Bennett. "All parties must do more to safeguard civilians".
So far, data from SIGAR on USA bombs dropped in Afghanistan in 2019 is available only for the months of January and February.
But the Taliban have refused to negotiate directly with Ghani's government, even as they hold talks with a USA peace envoy.
"The best way to end the suffering of non-combatants is to end the fighting through an agreed-upon reduction in violence on all sides", said Col Butler.
A single mortar attack incident by Daesh on 7 March 2019 in Kabul caused approximately one-fifth of all civilian casualties from ground engagements, the report says, adding that the use of IEDs was the second leading cause of civilian casualties.
"We hold ourselves to the highest standards of accuracy and accountability". "We strive for precision in all of our operations".
UNAMA's report did, however, also find that civilian casualties dropped 23 percent compared with the first three months of 2018. All four attacks were attributed to Taliban.
"It's not just my family, there are dozens of families just like mine who have been lost in bombings", Rahman told The Associated Press this week.
The bloody milestone comes as the USA steps up its air campaign in Afghanistan while pushing for a peace deal with the Taliban, who now control or influence more parts of the country than at any time since they were ousted in 2001.
"A shocking number of civilians continue to be killed and maimed each day", said Tadamichi Yamamoto, the United Nations secretary-general's special representative for Afghanistan.
While the US war in Afghanistan was bloodiest in its infancy, little data is available until 2009, when the United Nations started keeping track of civilian casualties and the USA started accounting for the bombs and munitions it drops on the country.
UNAMA recalled that a total of 3,804 Afghan civilians were killed in 2018, the deadliest tally so far.
The findings mark the first time since systematic documentation of Afghan civilian casualties began a decade ago that the Afghan military and its global supporters were responsible for more noncombatant deaths than their adversaries on the battlefield, UNAMA said.