HONG KONG — China’s new president, Xi Jinping, sought to assure African countries on Monday that his government would heed complaints that relentlessly competitive Chinese companies were suffocating African efforts to nurture industry and jobs, and he promised aid, scholarships and technology transfers in an effort to counter those fears.

Mr. Xi delivered his defense of China’s economic stake in many African countries in a speech in Dar es Salaam, the seaside economic hub of Tanzania, where he arrived Sunday as part of his first tour abroad as national leader.

China has long boasted of its role under Mao Zedong as a supporter of African efforts to throw off Western colonialism, and Mr. Xi’s two-day visit to Tanzania has carried echoes of that past. On Sunday, he was greeted by hundreds of shouting well-wishers in an organized show of good will, Tanzanian and Chinese news reports showed.

But some African officials have voiced fears that China’s dominance as an exporter of cheap garments, appliances and other goods, and its appetite for unprocessed raw materials, have skewed economic ties and undermined African hopes to advance into industrial prosperity.