Sudanese conflict: What you need to know
4 May 2012 Last updated at 17:47 BST
Only 10 months after South Sudan gained its independence from Sudan, the two countries could be on the brink of all-out conflict.
The crisis started in April, after months of border skirmishes, when South Sudan seized an oil field, which is internationally accepted to be in Sudan, saying the area was being used as a base for Sudanese attacks on its territory.
Defined borders and how oil revenues will be shared are some of the issues still to be resolved by both countries.
Now the UN has given an ultimatum to Sudan and South Sudan to end fighting or face sanctions.
BBC Arabic's Omar El-Tayeb Ahmed explains the key facts behind the Sudanese conflict.