Staff at South Sudan’s largest oil hub are returning to work after fighting between the army and rebel forces forced some to temporarily evacuate, the East African country’s government said.

Some workers were removed from the Paloch fields in Upper Nile state as a precautionary measure on Wednesday, an oil ministry official, who asked not to be identified in line with policy, said by phone from the national capital, Juba. Rebels loyal to former Vice President Riek Machar said earlier this week that the fighters took control of the state’s oil facilities, a claim denied by the government.

There is no danger now and staff have returned with the support of extra government troops, the official said. Army spokesman Philip Aguer said his forces recaptured the nearby town of Melut on Wednesday, removing the threat to Paloch.

South Sudan has sub-Saharan Africa’s biggest oil reserves after Nigeria and Angola, according to BP Plc data. Its low- sulfur crude is prized by Japanese buyers as a cleaner-burning fuel for power generation. Before the war began, China National Petroleum Corp., Malaysia’s Petroliam Nasional Bhd. and India’s Oil & Natural Gas Corp. pumped most of the oil.

Upper Nile is the only state still pumping oil 16 months after South Sudan’s civil war erupted when a power struggle within the ruling party turned violent. The landlocked country exports its crude through pipelines across neighboring Sudan.