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At least 1,000 people are believed to have died in clashes in South Sudan between rival army factions - in a conflict escalated by ethnic undertones.

President Salva Kiir says the violence started after a coup attempt, blaming soldiers loyal to former Vice-President Riek Machar for the trouble. Mr Machar denies this.

The BBC outlines the background to the crisis - in 60 seconds.

Video produced by Michael Hirst

4 May 2012

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.

Overview of Sudan along with a timeline from the beginning of Sudan's independence to now.

This is the story of Salva Dut, founder of Water for Sudan. Salva Dut is one of the main characters in the story, "A Long Walk to Water" by Linda Sue Park.

Poem by PAUL LAURENCE DUNBAR