The operation took place in the late hours of January 31 and the wee hours of February 1. The US launched a battery of airstrikes in the Maiwand and Panjwai districts of southern Kandahar Province, followed by ground operations by Afghan special forces.
When the operation was finished, Afghanistan's National Directorate of Security bragged that they had killed 50 Taliban fighters, including several commanding officers.
But HRW launched their own investigation into the attack and claimed that witnesses told them that both the airstrikes and the ground operation led to civilian casualties. They estimated 20 civilian deaths occurred, including instances of Afghan special forces dragging civilians into the street to execute them.
"Summarily executing people in custody, whether they are fighters or civilians, is a war crime," said Patricia Gossman, a researcher at HRW, in the Wednesday report. She also called for "a prompt and impartial investigation."
HRW went on to claim that Kandahar security forces were guilty of systematic human rights violations, killing at least 61 civilians in 2017. "The Afghan government's failure to investigate past possible crimes by Kandahar's security forces makes an investigation of this incident all the more important," Gossman said. "Unlawful killings won't stop unless there is real accountability."
US Forces-Afghanistan spokesman Tom Gresback reiterated Kabul's claim in a statement that "all of those killed in the operation were identified as Taliban fighters." While he didn't announce an investigation, he did say that US Forces-Afghanistan "takes seriously all allegations of human rights violations reportedly committed by Afghan forces."
Stars and Stripes also interviewed Kandahar police spokesman Ahmad Zia Durrani, who claimed that the only two civilian casualties that occurred during the operation happened during a raid on a house.
He added that the civilians were both abetting the Taliban. "I'm 100 percent sure that these were the enemies of the Afghan people," Durrani said.
The Afghan Ministry of Defense promised to investigate the allegations, adding that they take such charges seriously.
In August, Kabul ratified the 1980 Convention on Certain Conventional Weapons as part of a campaign to win the hearts and minds of the Afghan people away from the Taliban. The convention bans the use of weapons such as landmines, incendiary weapons and booby traps in warfare and has been signed by 125 countries.
The UN reported in February 2018 that civilian casualties in Afghanistan have decreased by 23 percent between 2016 and 2017 as a result of Afghanistan's attempts to stem civilian deaths.