NEW : 72 of 5,500 new peacekeepers have arrived in Juba , the U.N. says . The United Nations has deployed a peacekeeping force to South Sudan for the first time since fighting broke out there last year. Group says it will take unspecified action if fighting does n't stop within four days . Fighting broke out between Kiir 's government and supporters of Machar on December 15 in the capital city of Juba . South Sudan 's government says it 's ready to adopt a cease-fire .
NEW : 72 of 5,500 new peacekeepers have arrived in Juba , the U.N. says . The United Nations has deployed a peacekeeping force to South Sudan for the first time since fighting broke out there last year. Group says it will take unspecified action if fighting does n't stop within four days . South Sudan 's government says it 's ready to adopt a cease-fire .