UNITED NATIONS - Hilde Johnson, the UN secretary-general's special representative for South Sudan, called for "the cycle of violence to stop" during a visit to the towns of Pibor and Fartait in Jonglei state, UN spokesman Martin Nesirky told reporters here Monday.

Jonglei state in South Sudan has been the scene of recent clashes between the Murle and Lou Nuer people, who have a history of conflict over cattle grazing land and resources in the area.

Nesirky cited Johnson as saying that "the safety and security of all must now come first." He said that she called for "a committed, coordinated, and cooperative drive by all concerned to achieve peace and stability" during her visit.

South Sudan is the world's newest nation and the UN's youngest member. It officially gained its independence from Khartoum on July 9, 2011.

"Ms. Johnson said that the situation in Jonglei was a major test for the newly independent South Sudan and she called on the government to take immediate steps to establish its peace team and move forward with urgency, working with church leaders, the communities and civil society," Nesirky said.

According to Nesirky, Johnson also expressed her concern about the humanitarian situation in Jonglei and urged the international community to respond to the needs in the area.

The spokesman added that there have been reports of further violence in Jonglei and that the number of casualties in the fighting, as published by some news outlets cannot be corroborated by the UN at this time.