The incident occurred on Monday when armed men opened fire on the residents, killing five.
Puok Nyang Tutjiek said hundreds of civilians, mainly women and children, are missing after they fled the bushes.
Puok accused suspected criminals from the Greater Pibor Administrative Area of carrying out the attack on Monday.
The attacks occurred during a peace dialogue between the communities of Akobo and the administrative area, which aimed to put an end to revenge attacks, cattle rustling, and the abduction of women and children.
“We condemn this act, and we still call for peace. This is disheartening because it was the right time for peace, as we have been mediating on some of the peace conferences,” he told Mingkaman FM.
However, Mingkaman 100 FM could not independently verify the claim after the phone calls to Pibor went unanswered.
The authorities blamed gunmen from Pibor for the similar attack that killed three people and wounded five others in Duk County last week.
Cattle raids, child abductions, and revenge killings have generally destabilized greater Jonglei.