China is blaming activists with "ulterior motives" for linking the Beijing Olympics to the nation's involvement in Sudan, with top officials saying they shared concerns over the humanitarian crisis in Darfur.

Games organizers and the Foreign Ministry responded Thursday to Steven Spielberg rejecting a role as an artistic adviser to the Olympics.

The film director withdrew on Tuesday on the grounds that China wasn't doing enough to pressure Sudan over the conflict in its western region of Darfur.

China is believed to have influence over the Islamic regime because it buys two-thirds of the country's oil exports while selling it weapons and defending it in the United Nations.

In their first response to Spielberg's announcement, Games organizers said his decision would not affect planning for the opening and closing ceremonies, adding: "We express our regret over his recent personal statement."

"The Chinese government has made unremitting efforts to resolve the Darfur issue, an obvious fact to the international community which holds unprejudiced opinions on this issue," the organizers, known as BOCOG, said in a statement e-mailed to The Associated Press.

"Linking the Darfur issue to the Olympic Games will not help to resolve this issue and is not in line with the Olympic Spirit that separates sports from politics," BOCOG said.

China is on the defensive against critics using the Games to spotlight the communist regime's curbs on human rights, press freedoms, and religion.

"It is understandable if some people do not understand the Chinese government policy on Darfur," Foreign Ministry spokesman Liu Jianchao said. "But I am afraid that some people may have ulterior motives, and this we cannot accept."

Liu said China was working with the United Nations to resolve the Darfur crisis.

"China is also concerned about the humanitarian crisis there, but we have been playing a positive and constructive role in promoting peace in Darfur," he said.

Liu said China supported a hybrid African Union and United Nations force to patrol Darfur.

"This did not come easily and our efforts have been applauded by the international community," Liu said.

Liu said 140 Chinese engineers helped prepare the hybrid force and Chinese companies in Sudan had helped dig wells and build small-scale power plants in Darfur.

"On the issue of Darfur, empty rhetoric will not help," Liu said. "What is more important is to do more things to help with the peace process there and alleviate the humanitarian crisis."

Fighting between government-backed militia and rebels in Darfur has killed more than 200,000 people and left an estimated 2.5 million displaced since 2003.