Israel and Jordan on Sunday barred pro-Palestinian US and European activists from trying to cross into the West Bank to deliver aid to students, a number of sources said.
More than four years after an African Union-UN peacekeeping force costing billions of dollars arrived in Sudan's restive western region of Darfur, peace remains elusive and some question the mission's value.
The UN has called an end to its observer mission in Syria, as activists reported more bloodletting in an attack on civilians in the main battleground of Aleppo.
The US is stepping up support for the Syrian rebels but, despite the failure of UN envoy Kofi Annan's mission, is sticking to its refusal to pour arms into a complex conflict.