The United Nations says the SPLA has been conducting military operations since last week in Wau County, Western Bahr el Ghazal State.
It raises concern about the violations of the ceasefire and implementation of the peace agreement.
According to a report by the Inner City Press, the SPLA forces are blocking Wau airport roads and restricting UN travel within Wau.
However, the SPLA says it has been pursuing criminals.
“That region has been inflected by different crimes of armed group including the (LRA). So the SPLA has the right to protect itself and pursue these criminals,” said Col Philip Aguer, spokesperson.
There have been reports of arrests of youth suspected of being sympathetic or members of the SPLM in Opposition in the state.
Meanwhile, at least 1,000 people have fled their villages in Wau County, Western Bahr al-Ghazal State, due to insecurity and are now camping in schools in the town, according to officials there.
County Commissioner Anthony Fada Ubur says the IDPs left Besselia area and arrived in the town this morning.