South Sudan rebels say the army forces have violated the newly-signed ceasefire agreement aimed at ending a brutal civil war in the landlocked African country.

Rebel spokesman, Dickson Gatluak, said on Sunday that a military convoy, consisting of two barges and seven gunboats, shelled rebel positions along the White Nile River while on its way from the county of Bor to Panyijar in Jonglei State.

“The cessation of hostilities started at midnight on Saturday but the government has broken it. They are not committed to it,” Gatluak added.

He noted that the rebels would on Monday report the situation to the Intergovernmental Authority on Development (IGAD), the regional bloc which helped broker the recent truce.

Neither the army nor the Juba government have commented on Gatluak’s remarks.

On August 26, South Sudanese President Salva Kiir signed the peace accord, which had been already signed by Riek Machar, the current rebel leader and former vice president. The truce came into effect on August 29, hours after fresh clashes between government forces and rebels.

On Saturday, both the government troops and revel forces traded blames for sparking fresh clashes before the ceasefire took effect.

South Sudan plunged into chaos in December 2013, when fighting erupted around the capital city of Juba between troops loyal to Kiir and defectors led by Machar.

The 20-month-long violence has left thousands of people dead and forced almost two million people from their homes. At least seven ceasefires have already been agreed and violated.