UNITED NATIONS - The UN Mission in South Sudan (UNMISS) is "deeply concerned" over the fighting in Juba, capital of South Sudan, UN spokesman Martin Nesirky told reporters Monday.

"The secretary-general's special representative, Hilde Johnson, urged all parties to cease hostilities immediately and exercise restraint," Nesirky said at a daily news briefing here.

"UNMISS will continue to monitor events closely," he said. "The Mission hopes the security situation in Juba will quickly normalize to enable the civilians to return very soon to their homes."

The Mission has confirmed that thousands of civilians have been seeking refuge in the UNMISS compound adjacent to the international airport and at UN House in the Jebel Kujur area since the fighting broke out on Sunday evening. A large number of the refugees are women and children.

In the meantime, peacekeepers are providing water and basic medical treatment to thousands of people who have fled to the UNMISS compound adjacent to the international airport and at the UN House in the Jebel Kujur area.

A new bout of fighting has forced an estimated 13,000 civilians to seek refuge at the UN base in Juba.