Updated Sept. 9, 2014 8:30 p.m. ET
KAMPALA, Uganda—China began deploying 700 soldiers to a United Nations peacekeeping force in South Sudan to help guard the country's embattled oil fields and protect Chinese workers and installations, a spokesman for the African nation's president said Tuesday.
The airlift of the Chinese infantry battalion to the South Sudanese states of Unity and Upper Nile, the site of the only operating oil fields still under the control of the central government in Juba, was expected to take several days, spokesman Ateny Wek Ateny said.
While Beijing's troops will operate under U.N. command, their posting to South Sudan marks a sharp escalation of China's efforts to ensure the safety of its workers and assets in Africa and guarantee a steady flow of energy for domestic consumption.
The deployment marks the first time Beijing has contributed a battalion to a U.N. peacekeeping force, U.N. officials said. In March 2013, China sent some 300 peacekeepers to Mali to protect Chinese engineers building a U.N. camp in the town of Gao.
China's state-owned National Petroleum Corp. holds a 40% stake in a joint venture that operates in South Sudan's vast oil fields. The company also has a 1,000-mile (1,600-kilometer) export pipeline that carries crude through neighboring Sudan to Port Sudan on the Red Sea.
Before the latest fighting in South Sudan flared, the country accounted for 5% of China's crude imports, according to the U.S. Energy Information Administration. Output has since plummeted by a third—to 160,000 barrels a day—following the outbreak of fighting late last year.
More than 10,000 people have been killed and some 1.5 million uprooted from their homes in South Sudan since fighting erupted in December between President Salva Kiir and forces loyal to his former vice president, Riek Machar.
The U.N. Mission in the Republic of South Sudan is authorized by the Security Council for up to 12,500 troops and 1,323 police personnel. As of July 31, it had a total of 11,389 soldiers, police and military liaison officers. Under its mandate, U.N. peacekeepers are allowed to use "all necessary means" to protect imperiled civilians at oil installations. If attacked, Mr. Ateny said, the Chinese soldiers are "combat-ready and can fight back."
Rebels fighting to depose Mr. Kiir's government have warned Beijing against taking sides in their fight.
"The Chinese should work under the mandate and command" of the U.N., said rebel spokesman James Gatdet Dak. "As long as they stick to that, we shall not have a problem with them."
The greater Sudan region has been a caldron of unrest for the past several years, with the kidnappings of Chinese workers by rebels in Sudan and civil war in South Sudan, which gained its independence from its northern neighbor in 2011.
Sudanese rebels in the South Kordofan region kidnapped dozens of Chinese road workers in 2012 and demanded that Beijing use its influence to compel the Khartoum government to halt an offensive against the rebels.
National Petroleum evacuated 97 of its staff from South Sudan's oil fields in December, shortly after Mr. Kiir accused Mr. Machar of launching a coup and fighting broke out. Since then, the forces of the two men have waged an 8-month battle, often over strategic oil fields.
China has sought diplomatically to ease tensions in the region. Beijing's envoys were key to resolving last year's oil export dispute between Sudan and South Sudan, which brought the two former civil-war foes to the brink of war.
But the outbreak of the current conflict presents Beijing with a new challenge.
Chinese officials have been working closely with western envoys to help end fighting between Mr. Kiir and his former vice president, even as both sides accuse the other of breaking cease-fire deals.