Chinese and African officials have rejected criticism of Beijing's development projects on the continent as they ended a summit that included a $60-billion pledge for more aid to the continent.

President Xi Jinping hosted leaders from across Africa  amid questions whether his country's Belt and Road global trade infrastructure initiative is worsening debt problems in some countries.

"Everything we do with China is perfectly under control, including on the financial and debt side," Senegal's President Macky Sall said on Tuesday at the end of the two-day summit.

"We shouldn't let our conscience be disturbed by criticism made regarding the nature of our relations with China," Sall said.

South African President Cyril Ramaphosa said one of the summit's main achievements was an agreement to "work hard to increase Africa's value-added exports to China".

For his part, Xi said the summit "opened a new chapter in the history of China-Africa relations".

Debt forgiveness

On the opening day of the summit on Monday, Xi offered $60-billion in financial support to African countries over the next three years. He said the debt of the continent's poorest nations will be written off.

The Chinese president said the figure included $15-billion in grants, interest-free loans and concessional loans, a credit line of $20-billion, $10-billion for "development financing" and $5-billion to buy imports from the continent.

Chinese companies will be encouraged to invest no less than $10-billion in African countries in the next three years, he added.

The money comes on top of $60-billion offered at the last summit in 2015.

China's special envoy for African affairs, Xu Jinghu, said Beijing would be "very conscientious" in its cooperation with Africa and conduct feasibility studies before choosing projects.

"China has not increased the debt burden of Africa," she told reporters.

Costly aid

Xi's cherished Belt and Road project has already seen China loan billions of dollars to countries in Asia and Africa for roads, railways, ports and other infrastructure projects.

Critics have warned that the Chinese leader's pet project is burying some countries under massive debt.

Beijing loaned around $125-billion to African nations between 2000 and 2016, according to data from the China-Africa Research Initiative at Washington's Johns Hopkins University School of Advanced International Studies.

A study by the Center for Global Development, a US think-tank, found "serious concerns" about the sustainability of sovereign debt in eight Asian, European and African countries receiving Chinese funds.

Locals in some countries have complained about the practice of using Chinese labour for building projects and what are perceived as sweetheart deals for Chinese companies.

The concerns are likely to grow as countries in other parts of the world begin to question whether Chinese aid comes at too high a price.

"Time has come for African leaders to critically interrogate their relationship with China," an editorial in Kenya's Daily Nation said on Monday.