China's special envoy on African Affairs, Zhong Jianhua, started a tour of African countries on Wednesday to discuss the South Sudan issue, the latest effort of Chinese government to help restore peace and stability in South Sudan.

The tour, which will include visits to Ethiopia, Uganda and Kenya, began on the day that the remains of Chinese UN peacekeepers Li Lei and Yang Shupeng were returned to China, arriving in Zhengzhou, Henan province. Li and Yang were killed on July 10 in Juba, capital of South Sudan.

Thirteen Chinese peacekeepers have been killed since China began UN peacekeeping missions.

Foreign Ministry spokesman Lu Kang said in a statement on the ministry's website that China asks for greater focus and investment from the international community to promote the easing of tension in South Sudan.

"Although both sides in the conflict in South Sudan have declared a cease-fire, the situation there remains complex and grave, and what future developments can be expected is shrouded in uncertainty," Lu said.

Special envoy Zhong will exchange views with the parties concerned in South Sudan crisis and discuss continued support for the mediation efforts of the Intergovernmental Authority on Development. He will urge the conflicting parties to implement the peace agreement signed last year.

By the end of 2015, China had sent more than 2,700 troops to African UN peacekeeping bases, according to Xinhua News Agency.

In December, China promised at the Johannesburg Summit of the Forum on China-Africa Cooperation that it would provide $60 million in free aid to the African Union to support the creation and operation of the African Standby Force and the African Capacity for the Immediate Response to Crisis.