The leaders of Sudan and South Sudan agreed on Saturday to demilitarize the disputed border area between them.

According to an African Union mediator, Presidents Omar al-Bashir, the military dictator of the largely Arab and Muslim north, and Salva Kiir Mayardit of the partly Christian South agreed after two days of talks in Ethipia “that actions should be taken as soon as possible to implement all the existing agreements unconditionally.”

The institution of a buffer zone was part of the agreement under which the South seceded from the African country. As of Saturday, they had yet to comply with the deal.

A 2005 peace deal failed to permanently resolve the border issue. Most of the former unified Sudan’s oil reserves are situated in the area. Landlocked South Sudan accounts for two-thirds of the country’s oil production but needs access to northern pipelines and port facilities to sell overseas. Its main customer is China which, despite pleas from Juba, has refused to intervene in the dispute.

South Sudan pumps around 350,000 barrels of petroleum per day, according to government data. The north needs the entirety of its oil production, some 115,000 barrels per day, to meet domestic demand. Before the South declared independence in 2010, Sudan sold more than 60 percent of its oil to China.

The north confiscated South Sudanese oil exports in January of last year to make up for what it said where unpaid transit fees. As recently as last April, hostilities broke out when Sudanese air forces reportedly bombed oilfields and the South attacked a border town.

In August, the government in Khartoum agreed to continue Southern oil transfers at a fee of nearly $9.5 per barrel. South Sudan agreed to pay more than $3 billion in addition to fees to get the oil flowing again. $3 billion more is supposed to be paid by outsiders to satisfy the north.