BEIJING: China said on Wednesday South Sudan's President had cancelled the Shanghai leg of his official visit to the Asian nation, but did not say whether he was returning home due to the growing unrest there.

Kiir arrived in China on Monday as violence between the world's newest nation and Sudan intensified, prompting him to accuse Khartoum of declaring war on his country in talks with his Chinese counterpart Hu Jintao.

"President Kiir has cancelled his trip to Shanghai," Chinese foreign ministry spokesman Liu Weimin told reporters, adding he would still attend talks with Vice Premier Li Keqiang and parliamentary chief Wu Bangguo Wednesday afternoon.

But Liu refused to indicate whether Kiir's cancellation of his visit to the Chinese commercial hub indicated he had cut short his entire visit, which was due to last until Saturday.

In the latest bout of violence between Sudan and South Sudan which gained independence last July at least 16 civilians were killed and 34 others wounded in Sudanese air raids on its neighbour's Unity state.

Liu also said Zhong Jianhua China's special representative on African affairs would visit Sudan and South Sudan in a bid to "promote peace talks".

China has been a key ally and the largest economic partner of diplomatically isolated Khartoum.

But the south's split from Sudan in July 2011 and recent clashes have forced a Chinese juggling act to maintain support for Khartoum while not alienating the south, the source of most of former Sudan's oil.