On Tuesday, filmmaker Steven Spielberg quit as artistic adviser to the 2008 Olympics in Beijing over China’s policy on the conflict in Darfur. That same day, 120 members of the US House of Representatives signed a letter to Chinese President Hu Jintao, urging him to take stronger action to push Sudan into ending the crisis in the Darfur region. China responded to these on Thursday, saying “ulterior” motives were behind some criticism of its actions in Sudan, and that the problems there should not be linked with the Olympics.• What is the Darfur crisis?Since 2003, the Arab-dominated government in Sudan, thorough the use of government forces and Arab militia, has been fighting ethnic African rebels in Darfur. The struggle essentially arose due economic deprivation in the region. Five years of fighting has killed more than 200,000 people and chased 2.5 million into refugee camps. Most victims of the violence are black African Muslims, attacked by ethnic Arab militias allied with the government; the government denies backing them. In recent months fighting among various rebel groups has added to the chaos.• What is China’s role in Darfur?While China does not play a direct role in the conflict, several countries and civil-rights bodies have criticised it for not leveraging its influence with the Sudanese government to resolve the problem. There are accusations that a part of China’s oil bill is paid in the form of arms. • Why does Sudan lean on China?China is Sudan’s key political and economic ally, investing in the country and importing more than two-thirds of Sudan’s oil output. China has threatened to veto UN sanctions against Khartoum.• What is China’s response to the accusations?China maintains it plays a constructive role in seeking to resolve the Darfur conflict. Last year, it began deploying 315 noncombat troops to Darfur to prepare for a proposed 26,000-member African Union-UN peacekeeping force that has been delayed in part by al-Bashir’s insistence that participating troops be verwhelmingly African.