Chinese-made Fantan fighters have been seen at Nyala, Darfur

The foreign ministry said Liu Giujin was ambassador to Zimbabwe and South Africa and is "an experienced diplomat (who) knows African affairs well".

Earlier this week, China denied claims they supplied arms to Sudan for use in Darfur, in breach of a UN arms embargo.

China has major oil interests in Sudan but is accused of blocking moves to end the appalling violence in Darfur.

Unless China does its part... history will judge your government as having bank-rolled a genocide Congressmen letter Quick guide: Darfur Pressure builds

The United Nations says more than 200,000 have died in Darfur during the four-year conflict and at least 2m have been displaced and live in camps.

More than 100 US congressmen have just sent a strongly worded letter to China's President Hu Jintao saying Beijing's 2008 Olympic Games could be affected if China fails to try to halt the bloodshed in Darfur.

"It would be a disaster for China if the Games were to be marred by protests, from concerned individuals and groups, who will undoubtedly link your government to the continued atrocities in Darfur, if there is no significant improvement in the conditions," the letter said.

"Unless China does its part to ensure that the government of Sudan accepts the best and most reasonable path to peace, history will judge your government as having bank-rolled a genocide," it said.

Embargo

Under the terms of a UN Security Council resolution passed in March 2005, an embargo is in place on the supply of arms to all parties in the conflict in Darfur.

The Sudanese ambassador to the UN, Abdel Mahmood Abdel Haleem, said the Amnesty allegations were "baseless and unfounded".

But the human rights group says Russia and China are aware of the eventual uses of arms exported to Sudan.

It cites 2005 trade figures as showing China sold $24m and Russia $21m of military material to Sudan.

China has a close relationship with Sudan, increasing its military co-operation with Khartoum earlier this year.