Syrian rebels routinely kill captured soldiers and suspected regime informers, human rights monitors said Thursday, March 14, warning of mounting war crimes committed by those trying to topple President Bashar Assad.

Abuses by the Assad regime remain far more deadly, systematic and widespread, particularly attacks on civilians with imprecise battlefield weapons, including widely banned cluster bombs, the London-based group Amnesty International said, according to The Associated Press.

The frequency and scale of such attacks has increased in recent months, the group said in twin reports released Thursday. The reports detail the conduct of the regime and rebel fighters. Previous reports about regime abuses received wide coverage.

Still, rebel fighters, who have generally enjoyed public sympathy in the West, must also be held accountable, said Cilina Nasser of Amnesty. "It's time for the armed opposition groups to know that what they are doing is very wrong, and that some of the abuses they committed amount to war crimes," she said.