"The heavy fighting in Juba town has forced more than 7,000 people to seek protection at UN House in Jebel and the Tomping compounds," the United Nations Mission in South Sudan (UNMISS) said in a statement.

The UN also accused combatants of preventing civilians from entering UN camps and slammed the alleged use of heavy weapons, including rockets fired from attack helicopters, close to UNMISS protection sites.

In the last 24 hours, 67 people were injured in or around UN safe zones, eight of whom later died, UNMISS claimed.

South Sudan, recovering from two years of civil war after President Salva Kiir accused his former deputy-turned-rebel leader Riek Machar of a coup attempt in December 2013, was again plunged into violence last Friday by forces loyal to the same leaders.

The renewed fighting comes barely two months after the formation of a transitional government of national unity.