NAIROBI South Sudan's government has released a United Nations aid worker after detaining him for nearly a month, a top U.N. official said late on Thursday.
Other aid workers have been detained since civil war broke out in 2013 in South Sudan, which is increasingly split along ethnic lines, and at least 82 have been killed, including six in a single ambush last month..
In February, the U.N. declared parts of the country were suffering from famine, the world's first in six years. This week the government announced it was hiking annual registration fees for international charities from $600 to $3,500.
"We are relieved to learn that Peter Alex, a World Food Program aid worker detained by the Government of South Sudan since April 10, has finally been released and reunited with his family," Nikki Haley, the U.S. ambassador to the U.N., said.
"Unfortunately, this is not a unique incident in South Sudan, the most dangerous country in the world today for aid workers," the statement from Haley said.
The United States has accused South Sudanese President Salva Kiir of contributing to the famine, and called on all sides to stop fighting.
"The warring parties in South Sudan must stop the ongoing violence," Haley said. "The Government of South Sudan must stop obstructing humanitarian assistance and ensure the safety and security of all humanitarian aid workers."
Alex was South Sudanese, a Nairobi-based spokeswoman for the World Food Programme said.
A South Sudanese government spokesman said that Haley's statement was "unfortunate".
"The reality on the ground contradicts the very statement," deputy minister of information, Akol Paul Kordit, said.
"We as the government are aware of the challenges that are facing us in terms of security, whether insecurity to aid workers or even to our own citizens ... This is something we have committed ourselves to work on to stabilise the country."
He also rejected the possibility that governments troops had attacked a U.N. peacekeeping base in Leer, a small northern town in the oil-producing part of the country.
The U.N. Mission in South Sudan (UNMISS) said its base came under fire from the direction of a government-held town on Thursday in an area where the country's main rebel force controls some towns and villages.
"This is untrue and baseless," he said. "If the UNMISS force or unit in that area came under attack, what is required from UNMISS is not a rush to judgment prior to a proper investigation."
(Editing by Louise Ireland)