New Delhi, March 11 -- The United Nations Mission in South Sudan said Monday that it would not comply with a government order to shut down its base in Akobo, an opposition stronghold near the Ethiopian border where tens of thousands of refugees have fled.

On Friday, the South Sudanese army ordered U.N. peacekeepers as well as humanitarian organizations and civilians to vacate the town ahead of a planned assault.

But the mission refused to leave and said it would provide "a protective presence for civilians" in the town, adding that the safety and security of its personnel "must be fully respected at all times."

The U.N. Mission said it was engaging "intensively with national, state and local stakeholders" regarding this order. "Any mil...