NAIROBI (Reuters) - Heavy gunfire erupted in the South Sudanese town of Wau on Monday, as residents said militias aligned to the government were going house to house searching for people from other ethnic groups.
Streets were deserted and most locals were staying inside, people who said they were in the town told Reuters by phone.
There was no immediate comment from the government and U.N. officials said they were monitoring the situation, without giving more details.
"Armed militias are moving from house to house," one person said, asking not to be named.
"It is an ethnic crackdown and it is been backed by cattle herders and armed civilian men from the Dinka tribe ... I am now hiding."
Another said he had fled an attack in the northwest town that had killed many people, including his cousin.
Both described members of the president's Dinka group searching for members of the local Lou and Fertit groups.
South Sudan descended into civil war in 2013 after President Salva Kiir, a Dinka, fired his deputy, Riek Machar, a Nuer. Fighting since then has often split the oil-producing country along ethnic lines and created a patchwork of armed factions.
The war in a territory already awash with weapons after decades of conflict has fuelled ethnic tensions over land, grazing grounds and long-running feuds.
Another resident said soldiers had blocked off a road leading to a civilian encampment protected by U.N. peacekeepers. More than 200,000 people have taken refuge in such sites set up across the country after widespread ethnic killings, many by soldiers.
"We are aware of the situation in the town and we are looking into it," U.N. spokesman Daniel Dickinson said.
(Editing by Louise Ireland and Andrew Heavens)