A U.N. expert panel has concluded that President Bashar Assad's forces and pro-government shabiha fighters perpetrated war crimes and crimes against humanity on Syrian civilians.

The panel appointed by the U.N.'s 47-nation Human Rights Council blames government and allied militia for the killing of more than 100 civilians in the village of Houla in May, nearly half of them children.

It says the murders, unlawful killing, torture, sexual violence and indiscriminate attacks point to involvement of the highest levels of government and forces.

The panel also concluded in its final report Wednesday to the Geneva-based council that anti-government armed groups committed war crimes, including murder, extrajudicial killings and torture, but on a lesser frequency and scale.