Ten members of one family - including seven children - were killed in an American strike on a car in Kabul, a relative of the dead told CNN.
The United States has launched an airstrip in Kabul, targeting an ISIS-K suicide bomber and threatening the airport, "the US Central Command said on Sunday.
The youngest victims of Sunday's plane crash were two two-year-old girls, according to family members.
Relatives found the remains of one of the girls, Malika, in the rubble near their home on Monday. A family member told CNN that it was unclear whether Malika was inside the car or compound when the strike came.
They have become "a normal family," said the brother of those killed. "We are not ISIS or Daesh and this has been a family home - where the brothers lived with their families."
Relatives of the victims spent Monday at Kabul Hospital pointing out the remains were separated from the coffins. Two-year-old girls, Malika and Sumaya, were among the names written on the coffins.
At the funeral, which was held later in the day, family members shouted "Death in America."
General Maj. Joint Staff General William Taylor told a news conference Monday: "We are aware of the reports of deaths. We take these reports very seriously."
On Monday, Pentagon spokesman John F. Kirby said the US was working hard to prevent casualties. "We are investigating this. I will not go through it. But if we have verified information to take innocent people here, then we will be open about that, too. No one wants to see that happen."
"But you know what else we didn't want to see happen. We didn't want to see what happened that we believe to be very real, very obvious and very close to Hamid Karzai Airport and our troops working at the airport as well as the citizens around us and that's one of our biggest concerns."
Neighbors and witnesses at the Kabul strike center told CNN that several people, including children, were killed.
"All the neighbors tried to help and brought water to put out the fire. I saw that five or six people had died," a neighbor told CNN. "The father of the family and another young boy had two children. They were dead. They were in pieces. There were also two injured."
One neighbor told CNN that they estimated that there were up to 20 people killed in the strike, "there is not much left in their house and nothing can be seen, they are pieces."
Another witness told CNN that after the strike, neighbors and bystanders "removed six bodies" and believed there were "missing children."
The U.S. military said in a statement on Sunday that "a major explosion in a car has indicated a high number of casualties," and that "it is likely to create more casualties."