Internally Displaced Persons (IDPs) prepare food at a temporary camp near Juba International Airport 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)

UNITED NATIONS, Feb. 23 (Xinhua) -- Head of the UN Mission in South Sudan David Shearer on Thursday stressed the need to improve security to reinvigorate what has been called "the bread basket" of South Sudan at a time when part of the world's youngest country is facing famine, a UN spokesman said here.

"Mr. Shearer was making his first field trip to the town of Yambio in the Western Equatoria region, an agricultural region which has typically provided a wide range of food products for the rest of the country," UN spokesman Stephane Dujarric said at a daily news briefing here.

"Production has slowed because farmers are no longer able to plant crops due to ongoing insecurity and displacement," Dujarric said. "Mr. Shearer said that security was also essential on the road network to allow trade and the distribution of agricultural products."

South Sudan, which gained independence from Sudan in 2011, has been suffering from food shortages exacerbated by a civil war that broke out in December 2013 with fighting between factions associated with President Salva Kiir and his former Vice President Riek Machar.

Between January and March 2016, 2.8 million people were in need of urgent humanitarian assistance, equivalent to almost a quarter of the population, with 40,000 in the conflict-torn Unity state particularly close to starvation, UN agencies said.

This week, the United Nations declared famine in a patch of South Sudan.

Famine was last declared in Somalia in July 2011 after an estimated 260,000 people had died, mostly in a two-month period.