What new violence in South Sudan spells for the region

Addis Ababa — South Sudan's rebel leader is warning attacks by government troops on rebel-held areas could sabotage a peace agreement.

Riek Machar told reporters in Ethiopia Monday that the South Sudan government is not respecting the cease-fire.

"The cease-fire has not been respected by the government since it was declared ... they still are on the offensive," Machar said. "If this situation goes on, it means the peace agreement is not implementable."

Both sides agreed to a cease-fire that took effect Sunday, but there are reported violations in the volatile states of Upper Nile and Unity.

Machar accused government troops of attacking despite the cease-fire and urged President Salva Kiir's government to control its troops.

From their side, South Sudanese officials accused rebels of launching fresh attacks on Monday.

The rebels ambushed a government army vehicle traveling between Leer town and the Thar Jath oil fields, Unity state acting governor Stephen Takel told The Associated Press by phone. Two government soldiers were killed in the attack, said army spokesman Col. Philip Aguer. The rebels also shelled government positions at Gabat area of Manyo County in Upper Nile state, without mentioning casualties, said Aguer.

But a rebel official denied there had been any clashes in the area Sunday or Monday. Leer county rebel commissioner Kuong Kuony said by phone from Unity state accused the government of sending a platoon of troops on foot out from Leer town, against the cease-fire's requirements that soldiers should remain in their barracks.

It is not possible to independently verify the alleged violations.

The U.S. has threatened U.N. sanctions against those who violate the pact, which was mediated by regional leaders and is backed by the international community.

Patinkin contributed to this report from Juba, South Sudan.