Akobo in eastern South Sudan grew nearly empty after the army issued an evacuation order aimed at making way for a military operation, prompting thousands of civilians to flee the opposition-held town, according to officials March 8.

The departures began Saturday night and continued into Sunday, with Nhial Lew, a local official in charge of humanitarian affairs, saying the town was “now almost empty.” Lew said women, children and the elderly had left and crossed into Ethiopia.

Officials said the army’s deadline to evacuate was set to expire Monday afternoon, but fighting was already reported west of Akobo beginning Saturday. Lew said Sunday evening that “we are hearing the sound of machine guns approaching.”

The South Sudan People’s Defense Forces, the national army, ordered the United Nations mission in South Sudan, UNMISS, to close its Akobo base on Friday. Nongovernmental organizations and civilians were also told to evacuate, the army said, “in order to avoid unnecessary collateral damage,” as the government prepared a military assault targeting “Akobo and surrounding areas,” according to a statement by military spokesperson Lul Ruai Koang.

Akobo is among the last strongholds of the Sudan People’s Liberation Movement-In Opposition, SPLM-IO, led by detained vice president Riek Machar. The army and political conflict follows a fragile peace framework between Machar and President Salva Kiir that has “nearly collapsed since fighting resumed between their forces last year,” the report said.

In Jonglei state’s north, confrontations have increased dramatically since December, when opposition forces captured government outposts. A government counteroffensive that followed displaced more than 280,000 people in a few weeks, the report said.

The town had been seen as a relatively safer haven, in part because more than 82,000 displaced people were seeking refuge in and around Akobo, where a small contingent of U.N. peacekeepers had been present. UNMISS had not officially responded to the government’s order to shut down its base as of Sunday.

The report said two U.N. flights evacuated most humanitarian workers on Sunday, while the International Committee of the Red Cross runs a surgical unit at the Akobo County Hospital. The ICRC had not yet evacuated its staff, and local health officials said fear of an imminent assault was complicating care for wounded patients.

Dual Diew, the Akobo County health director, said Sunday that medical staff were worried for patients at the hospital and that they “tried to make a plan to take them to a safer location, but we don’t have enough fuel.” He described how the ability to relocate patients depended on resources that were not available in sufficient quantity.

On Saturday, civilians in Akobo demonstrated against the army’s ultimatum and marched toward the U.N. base calling for peace and protection.