While Sudan has been the main source of arms and ammunitions in east Africa for decades, the latest report from the Conflict Armament Research Group may add to concerns in the region.
It shows that weapons and ammunition captured by pro-government forces from opposition forces in Jonglei state late last year had come from neighbouring Sudan.
For Claudio Gramizzi, the group's main expert, the report proves the weapons are falling in the hands of south Sudanese rebels. But they also end up further away, in northern Kenya, for instance, and in the Central African Republic.
In Northern Kenya Turkana North MP Christopher Nakuleu claimed this week that a flow of guns are coming into the country from South Sudan, most of them of made in Sudan. The arms have been used by different tribes in pastoralists' groups, fueling more violence in a dry, poor region.
It is unclear whether Khartoum is deliberately supplying rebels. But for Roland Marchal, French senior researcher on central and east Africa, there will be no end to the trade without a political solution to the conflict.
The surge of Sudanese arms in east and central Africa might therefore worsen the weak political response to the ongoing conflict in South Sudan, with the looming danger of increasingly affecting the entire region.