Internally Displaced Persons (IDPs) wait to be airlifted to the South Sudanese Northern State of Eastern Nile, in Juba, capital of South Sudan, Jan. 7, 2017. Hundreds of IDPs have been stranded in Juba since December 2016 following the start of a voluntary repatriation program initiated by the South Sudan's government, to resettle people displaced by three years of civil war. (Xinhua/Gale Julius)

JUBA, Feb. 11 (Xinhua) -- Intense fighting in South Sudan has displaced 1.5 million people who have been forced to leave the country and seek safety since conflict erupted in December 2013, the UN refugee agency said on Friday.

The UN High Commissioner for Refugees (UNHCR) said in a statement that an additional 2.1 million people are displaced inside the world's youngest nation with no solution in sight.

"With this large scale displacement, South Sudan is now Africa's largest refugee crisis and the world's third after Syria and Afghanistan - with less attention and chronic levels of underfunding," UNHCR said.

Intense fighting broke out in South Sudan in July 2016 following the collapse of a peace deal between the government and opposition forces.

The UN agency said over 760,000 refugees fled the country in 2016, as the conflict intensified in the second half of the year - on an average of 63,000 people were forced to leave the country per month.

Some half a million had to flee in the last four months, it said, adding that over 60 percent of the refugees are children, many arriving with alarming levels of malnutrition - enduring devastating impact of the brutalities of the ongoing conflict.

"We are appealing on all parties involved in the conflict for an urgent peaceful resolution of the crisis, without which, thousands continue to arrive in South Sudan's neighbouring countries of Uganda, Ethiopia, Sudan, Kenya, Democratic Republic of the Congo and in the Central African Republic every day with the conflict now in its fourth year," it said.

The majority of the refugees are being hosted by Uganda, where some 698,000 have arrived.

Ethiopia is hosting some 342,000, while more than 305,000 are in Sudan and some 89,000 in Kenya, 68,000 in the Democratic Republic of the Congo and 4,900 in the Central African Republic.

According to the UN agency, recent new arrivals report suffering inside South Sudan with intense fighting, kidnappings, rape, fears of armed groups and threats to life, as well as acute food shortage.

"In 2017, we are seeking 782 million U.S. dollars for regional operations inside South Sudan and the neighbouring host countries," it said.

Those fleeing South Sudan are being hosted by the poorest communities in the neighbouring countries, under immense pressure with scarce resources.

UNHCR said it is extremely worried by the lack of resources to handle one of the world's largest refugee crises.

"We are working with authorities in South Sudan's neighbouring countries to provide life-saving support and look after the basic needs of those arriving in desperate conditions. However, our relief efforts are being hampered by severe underfunding," it said.