American air strikes in Somalia killed two civilians and injured three in February, Amnesty International said yesterday.
US Africa Command said it was assessing the allegations and goes to great lengths to avoid civilian casualties.
US forces have been fighting a decade-long struggle against the al-Qa'ida-linked militant group al Shabaab, which is trying to overthrow Somalia's shaky, internationally backed government.
Africa Command says air strikes are a key weapon against al Shabaab, but Amnesty says they also mistakenly target civilians.
A US air strike in the town of Jilib on February 2 hit a family having a meal, Amnesty said, killing 18-year-old Nurto Kusow Omar Abukar, injuring her two younger sisters - aged seven and 12 - and her 70-year-old grandmother. Amnesty cited an interview with the girls' father, who was present but uninjured in the strike.
"He was very devastated, he didn't know why his family was targeted," Amnesty researcher Abdullahi Hassan said. "He said, 'I'm now in my farm, alone in an open place, if they want to kill me.'"
Mohamed Omar Abukar, the son of the 70-year-old woman, said his family had been devastated by the strike.
"She is OK and walking. My mum and my niece Fatuma... are too seriously injured to be brought by car to Mogadishu."
Another strike on February 24 on the village of Kumbareere, about 10km north of Jilib, killed Mohamud Salad Mohamud, a 53-year-old father-of-eight who ran a banana farm, Amnesty said.
Africa Command - also known as Africom - issued statements after both strikes saying it had killed militants.
Amnesty researcher Mr Hassan said Africom should be more transparent about how it investigates allegations of civilian deaths.
"They seem to be living in denial that the air strikes actually kill civilians," he said.
Last year, Amnesty issued a report alleging 14 civilian deaths in five US air strikes in 2017 and 2018.
At the time, Africa Command rejected the report but later said a review had concluded that two civilians had been killed in a 2018 strike.