The helicopters arrived shortly after midday and sent a rocket hurtling into an area at the back of the crowd where children were sitting.
As people began to flee, witnesses said, heavy machine gun fire followed them.
It was the latest deadly example of how a ferocious new air campaign against the Taliban has caused a spike in civilian casualties from US and Afghan air operations.
This Afghan Air Force attack on 2 April in north-eastern Kunduz province killed at least 36 people and injured 71, the UN says. Although witnesses said Taliban fighters and senior figures were in the crowd, 30 of those killed were children.
Hundreds of people had gathered outside a madrassa in the Taliban-controlled district of Dasht-e-Archi to watch a group of students have turbans tied around their heads in a traditional ceremony to recognise their memorisation of the Koran.
“I saw turbans, shoes, arms, legs and blood everywhere,” one local resident told the BBC the next day, describing the aftermath. Everyone in the area knew the event was happening, and many children, he said, had turned up for the free lunch that was about to be served.
Since President Trump announced his Afghanistan strategy and committed more troops to the conflict last August, the number of bombs dropped by the US Air Force has surged dramatically. New rules of engagement have made it easier for US forces to carry out strikes against the…
