The government and opposition both issued statements claiming the other side had attacked their forces in Koch county, Northern Liech state, on Monday.

Representatives of President Salva Kiir and opposition leader Riek Machar signed a cessation of hostilities agreement in the Ethiopian capital Addis Ababa last week to allow humanitarian access and protect civilians.

The truce, backed by the east African Inter-Governmental Authority on Development (IGAD), came into effect Sunday.

“Riek Machar forces under Gatgok Khor attacked our positions today morning at 7.12 a.m. [local time (0412GMT)] in Koch county, Northern Liech state,” the government said.

It said the forces were shelled and repulsed the attackers. It also cited a cease-fire breach by Machar’s forces in Pagak, close to the border with Ethiopia.

The government called on IGAD and the international community to condemn the violations.

“We repulsed the attack, killing 23 of their soldiers while we lost four comrades,” he said. “Government forces attacked our base in Liech state.”

The truce -- the latest attempt to end the four-year civil war -- seeks to revive a 2015 peace deal.

Tens of thousands have been killed and a third of the population of 12 million have fled their homes in violence that first erupted in December 2013 when Kiir sacked his deputy Machar.

Previous truces have been broken as the fighting deteriorated to involve several armed groups.

The agreement is expected to pave the way for elections, the timing of which will be negotiated in upcoming talks.

There had not been a statement from IGAD or any other third party on the alleged violations.