UNITED NATIONS (AFP) - China will soon send an infantry battalion to reinforce the United Nations peacekeeping mission in war-torn South Sudan, officials said on Thursday.

In December, the Security Council voted to send an extra 5,500 peacekeepers - some re-assigned from other UN missions in Africa - to the UN mission in the world's newest country, bringing the total deployment there to 12,500.

More than half of these reinforcements have arrived.

UN peacekeeping chief Herve Ladsous confirmed on Thursday that China had agreed to send a "battalion" of 850 soldiers within the next few months.

He told reporters the UN "was in the process of deploying a Rwandan battalion" re-assigned from the UN mission in Darfur, and was expecting "in the next two weeks Ethiopian troops, additional Kenyan troops, and later, Chinese."

UN officials said this was the first time China will send a combat unit to a UN peacekeeping operation.

Beijing has participated in UN missions in Mali and Darfur, but only sent logistical and protection units.

The UN Security Council on Tuesday approved a resolution making defending civilians the highest priority task in the South Sudan mission.

The mission's other roles are to keep a close eye on the human rights situation, to help deliver humanitarian aid, and to watch over compliance of a truce signed by the rival sides but never respected.

The UN says crimes against humanity may have been committed by both sides in the conflict, supporters of President Salva Kiir and of his ex-vice president Riek Machar, and fears a famine may set in.

South Sudan only gained its independence from Sudan three years ago and has been ravaged by a conflict between rebel groups and the government since December 15, resulting in massacres and atrocities against thousands of civilians from both sides.

Around a million people have been displaced and many are living in extremely cramped and precarious conditions.