A bride and 46 of her guests - including 39 women and children - were killed by a US air strike in Afghanistan, an official inquiry has found.
The US military says it goes to "great lengths" to avoid civilian casualties, but fatal errors like this happen with depressing frequency.
It's not only the Americans, of course. The British have killed civilians and, just this week, fired on themselves.
The Afghan president, Hamid Karzai, has repeatedly called for more care in targeting and warned that his people's patience is wearing thin.
Journalist John D McHugh has reported on the difficulty of patrolling the remote border regions of Afghanistan. The Guardian's Declan Walsh has documented the plight of citizens.
The latest killings are likely to reignite debate about whether the military operations are helping or hindering the battle to win hearts and minds.
