NEW : If civilians were killed , deaths may constitute war crimes , he said . U.N. chief : Rebels in east Congo pose ` ` poisonous consequences '' for peace . Cease - fire in Congo unraveling in third straight day of fighting . Battles between warlord Joseph Wade 's rebels and civilians spreading , U.N. chief .
NEW : If civilians were killed , deaths may constitute war crimes , spokesman says . U.N. chief : Rebels in east Congo pose `` poisonous consequences '' for country . Cease-fire in Congo unraveling in third straight day of fighting . Battles between warlord Laurent Nkunda 's rebels and army spreading , U.N. says .