U.N. and African Union peacekeeping forces in East Africa have repeatedly allowed their weapons to fall into the hands of armed groups responsible for much of the region’s violence, according to a report by a Geneva-based research group.

The report by the Small Arms Survey concluded that more than 500 weapons, including heavy machine guns and mortars, as well as nearly 1 million rounds of ammunition, were taken from peacekeeping forces in Sudan and South Sudan over the past decade.

The arms were seized from peacekeeping patrols, bases and supply convoys in at least 20 separate incidents between 2005 and 2014, the report said. […]