On April 15 the SPLA said that the Sudanese government (Khartoum) had moved several thousand troops from the Nuba Mountains into south Sudans Upper Nile area (an oil producing area). On April 19 the SPLA accused Khartoum of violating the ceasefire agreement by shelling several villages in Western Upper Nile province. Specifically, the SPLA charged the government with violating the Agreement on the Protection of Civilians (APC).