Mediators say South Sudan's warring parties have failed to reach a final deal following days of negotiations in Ethiopia.

Ethiopian Prime Minister Hailemariam Desalegn said in a statement Friday that he regretted "the talks did not produce the necessary breakthrough."

South Sudanese President Salva Kiir and rebel leader Riek Machar had been given a March 5 deadline to finalize issues including power sharing, but mediators extended the talks until Friday in hopes the rivals could reach an agreement.

The threat of U.N. sanctions hangs over Kiir and Machar, as the U.N. Security Council this week unanimously approved the creation of a system to impose sanctions on those blocking peace in their country.

The conflict has killed tens of thousands of people.