JUBA -- South Sudan's army said on Sunday that at least 16 civilians have been killed and 22 others wounded including foreign nationals in the latest ceasefire deal violation.

Sudan's People's Liberation Army (SPLA) spokesman, Lul Ruai Koan told Xinhua by phone in Juba that rebel leader Riek Machar's Sudan People's Liberation Movement in Opposition (SPLM-IO) forces attacked government position in Southern Liech, Northern Liech States in former Unity state on Saturday.

"In Northern Upper Nile state, opposition forces loyal to Machar attack a cattle camp in Maban County leaving 16 civilians dead, 22 others wounded and livestock stolen," Koang said.

He confirmed that the agreement has been violated hours after President Salva Kiir and March ordered its implementation.

"Among the dead were three Ethiopian nationals that were doing business with the locals in the area," Koang added, noting that the rebels wanted to gain more territory before the permanent ceasefire became effective on Saturday.

The recent agreement which was inked between Kiir and Machar on June 26, declares a "permanent" ceasefire, and states that the parties will "agree on all the ceasefire arrangements including disengagement, separation of forces in close proximity, withdrawal of allied troops, opening of humanitarian corridors and release of prisoners of war and political detainees", all within 72 hours.

The parties also agreed on a "self-monitoring mechanism" as part of the deal and the agreement also invites regional bloc IGAD and African Union member states to deploy the necessary forces to supervise the ceasefire.

Koang called on the South Sudan's peace and ceasefire monitors to investigate where violations have been reported and appealed for violators to be punished.

However, SPLA-IO military deputy spokesman Lam Paul Gabriel accused government forces of attacking rebel positions on the outskirts of the northwestern South Sudanese city of Wau, barely six hours after the ceasefire took effect.

"The government troops attacked our positions and we responded in self-defense and this is because President Salva Kiir doesn't respect their words," said Lam.

Independent sources, however, said both government forces and rebels launched counter attacks on each other's positions on Saturday, just hours after the ceasefire went into effect.

South Sudan's conflict has now entered its fifth year. The conflict erupted in 2013 after forces loyal to President Kiir and his former deputy Riek Machar engaged in combat.

The 2015 peace agreement to end the violence was again violated in July 2016 when the rival factions resumed fighting in the capital, Juba, forcing Machar to flee into exile.

Millions of South Sudanese civilians have sought refuge in neighboring countries as the conflict rages on despite attempts by international players to end it.