At least 36,000 people have fled their homes in Juba since heavy fighting erupted in the South Sudanese capital on Friday, the United Nations said Tuesday.

At least 36,000 people have fled their homes in Juba since heavy fighting erupted in the South Sudanese capital on Friday, the United Nations said Tuesday.

"The latest fighting since Friday has displaced 36,000 people," Vanessa Huguenin, spokeswoman for the UN humanitarian agency OCHA, told AFP, speaking in French.

She added that the number was likely to "evolve" in light of the volatile situation.

OCHA said the displaced had sought shelter in sites run by the UN mission in South Sudan (UNMISS) and other locations across the city, adding that "most of the affected people are women and children."

The "recent fighting has had a devastating impact on the civilian population," the agency said in a statement, adding that heavy rains in parts of Juba had worsened the situation.

"Access to those in need is limited by the ongoing fighting and insecurity," it warned, stressing that "it is imperative that civilians are allowed to move freely to places of refuge, and that humanitarian staff and their assets are protected to allow immediate, safe and unhindered access to those in need."

OCHA's warning came as a fragile ceasefire called by both President Salva Kiir and his opponent Vice President Riek Machar appeared to hold in Juba on Tuesday after four days of gun battles.

The fighting in Juba began on Friday evening -- killing over 300 soldiers that day alone according to government estimates -- then paused on Saturday, the country's fifth anniversary of independence, before resuming with intense fighting on Sunday.

The violence has raised fears of a return to civil war that broke out in December 2013, characterized by ethnic massacres, rape, murder and the use of child soldiers.