NEW : U.N. officials hope to have reinforcements in South Sudan by Saturday . Peace talks `` very constructive , '' South Sudan 's foreign minister says . Fighting between rival ethnic groups has resulted in mass killings . They are again fleeing government troops battling rebel followers of Machar . TL;DR NEW
NEW : U.N. officials hope to have reinforcements in South Sudan by Saturday . Peace talks `` very constructive , '' South Sudan 's foreign minister says . Fighting between rival ethnic groups has resulted in mass killings . TL;DR NEW