 And news outside Africa out here have been clashes between Russian and US envoys at the UN Security Council after the US called on meeting to discuss Moscow's troop buildup on its borders with Ukraine. US Ambassador Linda Thomas-Greenfield said the mobilisation was the biggest Europe had seen in decades. Her Russian counterpart accused the US of fomenting hysteria and unacceptable interference in Russia's affairs. The US and UK have promised further sanctions if Russia invades Ukraine.