BEIJING - President Hu Jintao set out Tuesday on an eight-nation tour of Africa, a visit that underscores China's growing influence on the continent and its voracious appetite for energy to fuel its booming economy.

Perhaps the most sensitive stop will be Sudan, where the United Nations is pressing Hu to use China's leverage as a big oil customer to resolve the crisis in the Darfur region. Hu's 12-day journey will also take him to Cameroon, Liberia, Zambia, Namibia, South Africa, Mozambique and Seychelles.

Key themes of the trip will include strengthening business ties and following through on promises of aid, including debt relief and poverty alleviation.

Trade between China and Africa has quadrupled over the last decade, generating $40 billion in 2005. Beijing has also become a major supplier of aid, last year announcing $10 billion in assistance from 2006 to 2009.

China's official Xinhua News Agency said Hu will sign a number of accords and economic agreements, a move that may be aimed at smoothing over criticism of Chinese motives.

Xinhua said $3 billion in preferential loans was to be dispersed over the next three years to help African countries improve infrastructure, buy technological equipment and set up production facilities.

China will also send young volunteers to do aid work in Africa, build hospitals, provide anti-malarial medicine to 33 countries, and help build 100 new primary schools by 2009, Xinhua said.

While African governments have largely welcomed China's growing involvement, African workers and their supporters have criticized Chinese business practices and willingness to support corrupt regimes as harming labor and undermining attempts to strengthen good governance.

China, a permanent member of the U.N. Security Council, has resisted U.N. attempts to force Sudan's government to accept U.N. peacekeepers in Darfur. But Beijing recently called on Sudan to cooperate with the world body in finding a solution to the conflict, raising expectations that China is heeding the message.

More than 200,000 people have been killed and 2.5 million displaced in Darfur since rebels from ethnic African farm communities took up arms against the Arab-dominated central government in 2003.

Sudan's government has been accused of retaliating against civilians as well as supporting paramilitary groups from nomadic Arab tribes blamed for some of the worst atrocities in the conflict. Sudan's government denies the allegations.

In recent months the violence has spilled into neighboring Chad and Central African Republic.

Human Rights Watch says China should cooperate with the U.N., support the imposition of sanctions on Sudan and examine Sudan's human rights record if it is "to fulfill its international obligations and be seen as a responsible international power."

"Undertaking these steps will help demonstrate that China's interest in Sudan is not merely about ensuring its access to oil supplies but also about the welfare of the Sudanese people so devastated by the ongoing conflict," the New York-based group said in an e-mail announcing that it had sent a letter to Hu on the issue.

Xinhua said Hu will inaugurate an economic cooperation zone during his stop in Zambia, a Cold War-era ally and a key supplier of copper. Miners there have protested over abusive conditions at a Chinese-owned mine and Chinese political and economic influence became an issue in last year's presidential election.

In South Africa, which has complained the influx of cheap Chinese clothes could devastate the textile industry, Xinhua said China will make a donation of $2.6 million "as part of efforts to help the country in skill training and poverty alleviation."