BEIJING - China yesterday announced the appointment of a special envoy dedicated to the Darfur crisis as Beijing faces international pressure to do more to resolve the conflict and the possibility of an Olympic boycott if it fails to act.

The move came a day after a group of U.S. politicians demanded that China use its influence as one of Sudan's biggest trade partners to persuade the African nation to stop the bloodshed in Darfur.

It also followed the release of an Amnesty International report this week alleging that China and Russia breached a U.N. arms embargo by letting weapons into Sudan. Both countries denied the allegation.

China has been widely accused of not doing enough on Darfur, given that it buys two-thirds of Sudan's oil exports and sells weapons and military aircraft to the Khartoum regime. As a veto-holding permanent member of the U.N. Security Council, China has blocked efforts to send U.N. peacekeepers to Darfur without Sudan's consent.

But faced with intensifying criticism, Beijing has been trying to show that it is willing to help while not overly embarrassing or alienating Sudan's leadership.

In the latest step, Foreign Ministry spokeswoman Jiang Yu said Liu Guijin, a former ambassador to Zimbabwe and South Africa, has been appointed to the new post of special representative on African affairs and will focus on Darfur.

A letter to President Hu Jintao from 108 U.S. House members Wednesday suggested that unless China changed its approach on Sudan, the 2008 Olympics in Beijing could become a disaster for the Chinese rather than the image enhancer the government is expecting.

French politicians floated the idea of a boycott during their presidential race, and actress Mia Farrow has called on corporate sponsors of the Games to pressure China to do more on Darfur.

China has bristled at attempts to link the Games to Darfur, but analysts said the threat got Beijing's attention.

"This Olympic issue has got them moving," said Francis Kornegay, an analyst at the Center for Policy Studies in Johannesburg, South Africa. "They definitely don't want a global or even halfway successful boycott of the Olympics."

During a visit to Khartoum in February, China's president told Sudanese leader Omar al-Bashir he must allow a bigger U.N. role in trying to resolve the conflict. A senior Chinese diplomat visited a refugee camp in Darfur last month to further display Beijing's concern.