(CNN) -- South Sudan is facing a "huge humanitarian crisis" that requires support from the international community, the United Nations' refugee chief said Sunday.
Nearly 80,000 refugees have entered the nation from neighboring Sudan, where fighting has flared in the states of Southern Kordofan and Blue Nile, U.N. High Commissioner for Refugees Antonio Guterres said. And ethnic conflicts in South Sudan have displaced thousands, he said.
"My appeal is for the international community to stand by South Sudan and to support this country that became a sovereign state just six months ago to be able to cope with the challenges," Guterres told CNN in an interview via Skype from South Sudan.
Last weekend, some 6,000 armed men from the Lou Nuer tribe marched on an area of South Sudan's Jonglei state, which is home to the rival Murle tribe, attacking the town of Pibor.
Although the Lou Nuer fighters have left, following negotiations with U.N. peacekeepers and the South Sudan authorities, help is urgently needed for those who fled, the U.N. Mission in South Sudan said Friday.
Beyond ethnic tensions, deficient health and education systems and a lack of infrastructure are significant obstacles for the nascent nation, he said.
"This is a baby that needs to be nurtured. And the international community, which made such good efforts in order to make sure the baby was born, now needs to go on with those efforts in order to make sure that the baby grows up and becomes an adult partner of the international community," Guterres said.
Decades of civil war between the north and south, costing as many as 2 million lives, ended with a U.S.-brokered peace treaty in 2005.
But before South Sudan gained independence in July, human rights monitors expressed concerns that long-standing grievances could lead to violence consuming the region again.
The United Nations estimates that more than 1,100 people died and 63,000 were displaced last year by inter-communal violence in Jonglei, not taking into account the latest clashes.
U.N. flights have delivered thousands of tents, kitchen sets, blankets, jerry cans, plastic sheets, sleeping mats, mosquito nets and other essential items to refugee camps in South Sudan in the past two and a half weeks.
CNN's Jonathan Mann contributed to this report.