The South Sudanese leadership is failing its people, the United Nations has claimed. David Shearer, the UN representative in the country, accused leaders of being more interested in their political gains rather than in the safety of people, who have been bearing the brunt of a three-year-long civil war.

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Shearer's remarks came days after both South Sudan and the UN declared a famine in parts of Unity State, in the upper Nile region.

At least 100,000 people are facing starvation, and millions across the country are affected by food insecurity.

Many fear hunger will deepen as the conflict has spilled into the Equatoria region, considered one of South Sudan's breadbaskets.

The UN has now appealed for $1.6 bn (£1.2bn) to provide life-saving assistance and protection to 5.8 million people across the country.

However, fears that humanitarian assistance might be hindered have spread after the government increased work-permit fees for foreign aid workers from $100 to $10,000.

The European Commission announced an emergency aid package of $85m after the country declared a famine. The UK government also pledged support to assist civilians and ensure people get access to food, water and medicine.

Priti Patel, secretary of the UK's Department for International Development (DfID) said: "Children will die tomorrow, and the day after, and the day after that, until the South Sudanese authorities allow food and life-saving aid to reach those most in need.

"It is completely abhorrent that the government of South Sudan, who should be protecting its own people, are instead focused on fighting and not letting aid through, which is causing this famine. Perpetrators of attacks against innocent people should be in no doubt that the world is watching and that that they will be held to account."

The South Sudanese government maintains it is committed to respecting a peace deal signed in 2015 that aims to end the bitter civil war. The leadership has always rejected allegations of human rights abuses and denied allegations that the army targets civilians.

South Sudan conflict explained

The South Sudan conflict erupted in 2013 when President Salva Kiir, of the Dinka ethnic group, fired his deputy Riek Machar – from the Nuer group – who then became a rebel leader.

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Ethnic-related violence targeting Dinka and Nuer has killed an estimated 50,000 people, amid allegations of crimes against humanity committed by both sides, including rape, torture and the use of child soldiers.

At least 1.5m people have fled to other countries. The exodus has been deemed "Africa's worst refugee crisis".

More than 2m are internally displaced as the country is on the verge of a Rwanda-style genocide.

The conflict has been claimed for the famine, the first to be declared in any part of the world since 2011.

People are fleeing violence leaving their crops to rot in the fields. In addition, the heavy rainy season has made some roads inaccessible, hindering food deliverance.

Kiir and Machar have agreed on several peace deals – the last of which was signed in August 2015 – but have failed to control their troops, who have broken every ceasefire since 2014.

Machar fled South Sudan following deadly fighting in the capital Juba in July 2016.

IBTimes UK's exclusive interview with Machar:

He is currently in South Africa seeking medical treatment but, in an exclusive talk with IBTimes UK, Machar said he was ready "to go home".

His wife, Angelina Teny, also a member of SPLM-IO, told IBTimes UK she believes her husband can contribute to achieving peace in the war-torn nation which is on the verge of a Rwanda-style genocide.