At least 390 humanitarian workers have been successfully evacuated from South Sudan's restive Maban region where two humanitarian workers were injured early this week due to violence, organizations said on Saturday.

The South Sudan NGO Forum said increased attacks have forced aid agencies to suspend services except for life-saving and critical activities to communities around Maban where violence erupted on July 23 after a peaceful protest by local youth turned violent, leading to looting, burning of humanitarian premises and damage to aid vehicles.

"The increase in attacks on aid workers' is wrong, unwarranted and we are extremely disappointed," Pius Ojara, Director of South Sudan NGO Forum said in a statement issued in Juba.

Ojara termed the violence against humanitarian actors, including the most recent attack in Maban as unacceptable, saying it reduces aid workers' capacity to implement essential services and activities, leaving the most vulnerable people in South Sudan at greater risk of hunger and disease.

"Such senseless attacks hamper efforts by aid agencies and their staff who are working tirelessly in a challenging environment to help the most vulnerable people in need of life-saving assistance," he said.

In Maban, there was forceful entry into UNHCR and 14 other compounds by approximately 2,000 youth that resulted into looting, arson, destruction of vehicles, structures and other humanitarian assets and lifesaving supplies including medicines.

UNHCR said South Sudan hosts nearly 300,000 refugees, mostly from Sudan's South Kordofan and Blue Nile States. Over 144,000 of those refugees live in four camps in Maban County.

According to Ojara, while there was no loss of life, aid workers have been traumatized by the Maban attacks, saying services will continue in the four refugee camps hosting 141,548 Sudanese refugees.

The NGO Forum called for local authorities to investigate the incident and ensure that organizers and perpetrators are identified and are held accountable for the unacceptable attacks.

The NGO Forum also called for assurance from government for protection of humanitarian workers, assets and supplies in Maban.

South Sudan's conflict that has now entered its fifth year erupted in 2013 after forces loyal to President Salva 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 Sudan's civilians have sought refuge in neighboring countries as the conflict rages on despite attempts by international players to end it.