(CNSNews.com) - In a triple blow for China Tuesday, filmmaker Steven Spielberg ended his association with the 2008 Olympics; prominent figures, including athletes and Nobel laureates, criticized the communist government; and 120 U.S. lawmakers added their voices to the chorus of concern over continuing violence in Darfur.

The common theme: China's economic and diplomatic support for Sudan's Islamist government is widely seen as helping to prolong a conflict that has cost an estimated 200,000 lives in the fighting and associated famine and disease.

There was no immediate response from the Chinese government, which in recent weeks has stepped up its defense of its policies regarding Sudan, while condemning attempts to link Darfur with the Olympics.

The Beijing organizing committee in April 2006 named Spielberg, amid fanfare, as one of three foreign artistic consultants for the Games' opening and closing ceremonies. (The other two were Australian Ric Birch, who directed opening and closing ceremonies at previous Olympic Games, and Frenchman Yves Pepin, a multimedia show creator.)

The Academy Award-winning director later came under fire for his involvement, notably from actress Mia Farrow in a March 2007 Wall Street Journal op-ed piece that dubbed the Games the "Genocide Olympics."

Spielberg said in a statement Tuesday he was formally announcing the end of his involvement.

Although the Sudanese government bore the bulk of responsibilities for the "crimes" in Darfur, he said, "the international community, and particularly China, should be doing more to end the continuing human suffering."

Spielberg said he had repeatedly urged Beijing to use its influence with Khartoum, and had left his contract unsigned for a year because of concerns over China's failure to do so.

"My conscience will not allow me to continue with business as usual."

The Save Darfur Coalition praised Spielberg's decision, saying he had acted "with great moral principle."

"China has had ample opportunity to help intercede in Darfur, but has refused to use its influence to end the human catastrophe," said executive director Jill Savitt.

Farrow also welcomed the move, saying she hoped it would "influence other participants, sponsors, and supporters of the Olympic Games."

In a joint letter to President Hu Jintao, released Tuesday, prominent personalities including 13 Olympic athletes, Nobel Peace Prize winners including Elie Wiesel, lawmakers and entertainers, said that China as an ally of Sudan and a permanent U.N. Security Council member "has both the opportunity and the responsibility to contribute to a just peace in Darfur."

In a separate letter, 120 lawmakers urged Hu to use his "significant influence" with the Sudanese government.

Without a much stronger Chinese effort to convince Khartoum "to end its obstruction," limited progress made over the past year would be undone and the possibility of an expanded regional crisis would grow, they said.

Last Friday, the U.S. Senate unanimously passed a resolution calling on President Bush and other world leaders to provide the combined U.N.-African Union peacekeeping mission in Darfur with helicopters and crews.

The mission, known by the acronym UNAMID, assumed control of the peacekeeping function from an A.U. force on Dec. 31. About 9,000 of the planned 26,000 troops are currently in place.

Critics say the mission's deployment has been hampered by the lack of helicopters, and by Sudanese government obstruction, including a Jan. 7 army attack on a UNAMID supplies convoy.

China says that while it opposes interference in other countries' domestic affairs, it is playing a constructive role in Darfur.

Foreign Ministry spokesperson Jiang Yu at a recent press conference reiterated that China was the first country to promise and then send peacekeepers to Darfur, noting that a 140-strong engineering unit has arrived in the region.

However, although quickly okayed the Chinese deployment, it has delayed approval for other non-African contributions, including troops from Nepal, Thailand and Nordic countries.

The Save Darfur Coalition said Tuesday that although China supported a Security Council resolution calling for the UNAMID deployment, it only did so after working to weaken the text.

It also said China had doubled its trade with Sudan in the first half of last year.