South Sudan foes declare end to fighting

South Sudan's president and rebel leader have agreed to end fighting which has left tens of thousands of people dead and about 1.8 million displaced.

"We have committed to end the conflict and stop the war with immediate effect," President Salva Kiir said on Saturday after a two-day summit of East African leaders mediating between him and rebel leader Riek Machar.

The leaders of the Intergovernmental Authority on Development (IGAD) agreed to a request by Kiir and Machar, his former vice president, for an additional two weeks of negotiations on forming a unity government.

The IGAD leaders vowed to intervene militarily to end killings within the next 15 days.

They also warned any further violence would be met by a series of "strong measures", including travel bans, asset freezes and an arms embargo.

A power struggle between Kiir and Machar turned violent 11 months ago.

The conflict took on ethnic overtones between the president's Dinka community and Machar's Nuer people and was marked by a chain of revenge killings.