China has issued an unusually energetic call to its ally, Sudan, to do more to stop fighting in Darfur.
China supplies weapons to Sudan
The "humanitarian disaster" in the region was a grave concern to China's government, said its envoy Liu Guijin.
Mr Liu called for Khartoum to do more to speed up the arrival of peacekeepers in the region but he also criticised Darfur's rebel groups.
China is a key ally of the Sudanese government - buying its oil, selling it weapons and using its weight at the UN.
Mr Liu has just returned from a trip to Sudan which included Darfur.
He said he had been profoundly affected by things he had seen in the province.
He said he was also moved by the stories he had heard from Darfuris forced to flee their homes after five years of conflict.
China has been stung by Western accusations that it is colluding with the Sudanese government, and is eager to ensure the issue does not overshadow this year's Olympic Games in Beijing.
Last month, US film director Steven Spielberg pulled out as artistic adviser to the Olympics, saying that China had failed to use its influence on Khartoum over Darfur.
The BBC's Amber Henshaw in Khartoum says Beijing is keen to defend its economic interests but also wants to be seen to be taking a more aggressive stance against Khartoum in the run up to the Olympics.
She says when Mr Liu spoke to journalists in Khartoum last week he was much less outspoken.
Then he pointed out that China was a friend to Sudan and that the Chinese government was already doing a lot to work with the West over Darfur.
The United Nations says more than 200,000 have died in Darfur during the four-year conflict and at least two million have been displaced and live in camps.