U.N. says Sudan forces blocked access to site of Darfur attack
Tribal fighting, banditry and clashes between insurgents and government forces have ravaged Darfur since rebels took up arms against the central government in 2003
Somalia wants Ugandan troops to remain
Somalia PM says it could be a challenge for his country if Uganda withdraws its troops
Uganda says to pull out troops from Somalia over Congo charges
Ugandan troops form bulk of peacekeeping force battling al Qaeda-linked Islamist rebels in Somalia and their withdrawal could hand an advantage to al Shabaab