NAIROBI, Kenya — The leaders of the two Sudans are meeting at a regional summit in Addis Ababa today amid growing tensions between the neighbors over oil.

Salva Kiir, the president of South Sudan, and Omar al-Bashir, the leader of Sudan, were bitter civil-war enemies. Although the outright fighting is over, the suspicion and enmity are very much alive.

This week, South Sudan began shutting down its oil installations in protest over Khartoum confiscating southern oil, a move it says was to reclaim funds owed by Juba.

More from GlobalPost: South Sudan charges that Sudan steals oil

In the run up to the South's official independence last July, most analysts guessed that Sudan's shared oil would bind them together. Most of the oil lies in the south, but all the pipelines and refineries are in the north.

The two need each other, so the argument went. Instead it has proved increasingly divisive.

Earlier this week South Sudan struck a deal with Kenya to build a new pipeline to export the oil southwards, a move that might offer the south a way around the north. That has angered Khartoum. It's not quite make-or-break at the Addis talks, but fears of a return to conflict are growing.

More from GlobalPost: South Sudan, Kenya agree to oil pipeline

NAIROBI, Kenya — It started years, even generations ago. The tit-for-tat cattle raiding that kills hundreds of people in South Sudan every year, is getting out of hand.

It was the massacre of dozens, hundreds or even thousands (reports remain unclear) of Murle people by their Lou Nuer rivals in and around the town of Pibor in Jonglei state over New Year, that grabbed the world's attention.

The horror of that slaughter seems only to have fed the warriors' blood lust.

More from GlobalPost: UN troops step in to prevent ethnic violence in South Sudan

Every day this week it seems there is a new report of a fresh attack that leaves dozens dead. These attacks are regarded as being mostly revenge attacks by Murle on Lou Nuer.

The UN mission in South Sudan has tried to ease tensions however, it is not well enough manned, equipped or funded to police a territory the size of France while the fledgling government remains incapable.

More From GlobalPost: UN starts massive humanitarian effort in South Sudan

It is hard to see how the vengeful and deadly raiding can be halted, and every new death is a further blow to the fragile stability of the world's newest nation.