All sides have committed war crimes in Somalia's conflict this year, according to lobby group Human Rights Watch.
It says the worst abuses have been by Ethiopian soldiers, who are supporting the government against insurgents.
Ethiopians have often indiscriminately attacked civilian areas and looted hospitals, its report says.
While insurgents have fired mortars into residential areas and executed civilians, since Islamists were driven from power in Mogadishu last December.
Both Ethiopia and the Somali government have denied the claims, reports Reuters news agency.
In the latest violence, at least 15 people have been killed in two separate incidents in the Somali capital.
More than 1,000 people were killed this year in the heaviest fighting since 1991, as Ethiopian and government troops tried to drive the insurgents out of Mogadishu...BBC..
