(CNN) -- South Sudan's Council of Ministers has declared Jonglei state a "humanitarian disaster area" and called on international aid agencies to provide urgently needed humanitarian assistance.
The declaration came Wednesday during a council meeting led by President Salva Kiir Mayardit, according to a posting Thursday on the government's website.
Government spokesman Barnaba Marial Benjamin said the council asked that international relief agencies, including the United Nations, provide aid to the Lou Nuer and the Murle ethnic groups and to people in other affected areas in the state.
Marial said the council had resolved to deploy more forces to guarantee security. He further reported that the council had resolved to establish a high-level committee to effect reconciliation between the Lou Nuer and Murle.
The council of ministers directed the two ethnic groups to return women and children from both sides who have been abducted and to reunite them with their communities, Marial said. The council said the national forces were in full control of Pibor, in Jonglei.
The United Nations sent a battalion of peacekeepers to Pibor last week amid reports that members of the Lou Nuer tribe were marching toward the town, which is home to the Murle tribe, after attacking the village of Lukangol.
In a statement posted Thursday by the independent News Agency of South Sudan, Marial was quoted as saying the Lou Nuer should vacate Murle territory so that the government can deliver relief services there.
He appealed to the commissioners of Uror and Pibor counties to cooperate with the government to ensure the return of the abducted children and property of Lou Nuer and Murle communities.
The London-based Minority Rights Group International, a nongovernmental organization, condemned the attacks between the Lou Nuer and the Murle and called on the government to protect citizens from all ethnic groups.
"Competition between ethnic groups over scarce resources has escalated in South Sudan," said Chris Chapman, MRG's head of conflict prevention, in a statement posted on the group's website. "At the same time there is a security vacuum, leading to the formation of militia groups and a breakdown of traditional structures of authority. This will continue to threaten the stability of the new nation, unless the government acts quickly to ensure security, inclusive representation for all communities, and equitable access to land and natural resources."
Ethnic tensions in the South Sudan state of Jonglei have flared as tribes fight over grazing lands and water rights, disagreements that have dissolved into cattle raids and abduction of women and children.
Fighters first struck Pibor on Saturday, attacking a portion that was out of the reach of U.N. peacekeepers, said Col. Philip Auger of the South Sudan army.
Benjamin said most of the Murle had fled when they heard the Lou Nuer were approaching.
The nonprofit group Medecins sans Frontieres, also known as Doctors Without Borders, suspended its activities in Pibor County.
The group's clinic in Lukangol was "burned and looted," spokeswoman Emily Linendoll said, adding that its Pibor clinic "has been targeted."
The attack on Pibor followed reports last week that Lou Nuer fighters raided Lukangol, burning it to the ground and forcing thousands to flee toward Pibor.
At least 50,000 people have fled the violence in the state, said Quade Hermann, chief of radio at Radio Miraya, a U.N.-backed radio station in South Sudan.
U.N. Secretary-General Ban Ki-moon last week urged the groups to work with the government of South Sudan to find solutions.
The violence in Jonglei state is the latest to rock South Sudan, which officially gained its statehood in July after separating from the north.
"The attacks, which on the face of it appear to be cattle raids, have deeper underlying causes related to poverty, competition for scarce resources, the ubiquity of small arms left over from a decades-long war and marginalization of ethnic minorities," said MRG's Chapman. "In addition, the conflict between the Lou Nuer and Murle is taking on a dynamic of repeated revenge attacks, highlighting the need for the government to take urgent action to protect innocent civilians."
According to MRG's 2011 research, some groups feel that they are not represented by the political system, and that resources have been diverted to more populous ethnic groups, leaving them poorer with unreliable access to land and resources.