Tens of thousands of people have been killed in South Sudan's two-year civil war, the UN said, putting the death toll much higher than estimates by aid groups that operate in the country. 

An unnamed UN official told news agencies that 50,000 have died in the conflict, which is a fivefold increase of the toll previously reported by humanitarian agencies.

Fighting is still ongoing, despite a peace agreement between President Salva Kiir and his former deputy Riek Machar signed in August last year.

The two men's power struggle started in December 2013 and prompted a cycle of retaliatory killings along ethnic lines between Kiir's Dinka and Machar's Nuer people.


READ MORE: Little to celebrate on South Sudan's fourth anniversary


UN spokesperson Ariane Quentier in Juba told Al Jazeera that "tens of thousands" had been killed in the war but that the exact number was difficult to verify.

"The country has hardly any roads and besides that moving around is very dangerous. It is impossible for anyone in or outside the country to have exact numbers," she said.

The battle for control of South Sudan has repeatedly pushed the country to the brink of famine, with millions of people dependent on the UN and aid agencies.

In January, both sides of the conflict agreed to share positions in a transitional government, and in February Kiir reappointed Machar to his former post as vice president.

But despite the reconciliatory rhetoric there have been multiple clashes in the past weeks, according to Quentier.

Last month, the UN stated that South Sudan's warring parties were still killing, abducting and displacing civilians and destroying property. 


READ MORE: Q&A - the future peace in South Sudan


Ahmed Soliman, a regional analyst at Chatham House in London, said there was a lot of undocumented killing going on. "Since the August agreement, fighting even occurred in new areas."

"The UN is clearly not overseeing what is really happening on the ground. There is limited access, they are overstretched and mainly focusing on their camps," Soliman said.

"The actual amount of people suffering [in] this war is hard to tell," he added. "There are people dying of hunger and isolation in an attempt to flee the violence. To make a reasonable estimate of the people affected in the country is a very hard task right now."

Currently the UN peacekeepers are sheltering nearly 200,000 people at six protection sites in South Sudan.

Secretary-General Ban Ki-moon urged the leaders of South Sudan last month to respect the terms of a peace agreement that ended two years of civil war last year.

Source: Al Jazeera