China, one of the world's fastest growing economies, has pledged $20 billion in loans to Africa over the next three years, strengthening the ties between the world's second-largest economy and the resource-rich nations of the African continent.

The announcement came from the Chinese president Hu Jintao who opened the 5th ministerial conference of the forum on China-Africa cooperation in Beijing on Thursday, attended by leaders from 50 African nations.

The loan pledge is double the amount China agreed to lend to Africa at a similar event in 2009. Over the last decade, China has invested heavily in several infrastructure, energy and other projects in Africa.

"We want to continue to enhance our traditional friendship, rule out external interference and enhance mutual understanding and trust," Hu said.

"In the next three years, the Chinese government will take measures in the following five priority areas to support the cause of peace and development in Africa and boost a new type of China-Africa strategic partnership," Hu further stated.

The measures will include a $20-bn credit line targeted towards the development of infrastructure, agriculture, manufacturing and small and medium-sized businesses.

In addition, Hu said that China would assist in bringing the benefit of development to the African people, through building of technology centers, training of professionals, awarding scholarships to students, and also cooperation in healthcare.

Other areas of cooperation include transnational and trans-regional infrastructure development, people-to-people friendship through exchanges and visits between Chinese and African media, as well as cooperation for peace and stability in Africa.

Addressing at the forum, UN secretary general Ban Ki-moon said cooperation with China was ''creating opportunities for African countries to diversify their economies, create jobs and improve healthcare and education".

China is Africa's largest trading partner. The trade between the two sides has increased many-fold during the past three decades to a record high of $166 billion in 2011, up from 10 billion in 2000 and 1 billion in 1980, according to Chinese government data.

China's biggest African trading partner is oil-rich Angola with almost $25 billion and mineral-rich South Africa with over $22 billion, followed by Sudan, Nigeria and Egypt.

Africa is a main raw material source to fuel China's rapid economic growth, and a major market for its products.

The nations in the continent are becoming increasingly dependent on Chinese demand for its exports, and a Chinese economic slowdown will have adverse impact on African commodity exporters.

According to a report newly published by the South African Standard Bank, China could demand more meaningful engagement between Africa's private and public sectors on multilateral matters in the summit.

''Africa is fertile soil for the internationalisation of China's yuan, and Chinese and African interests also converge in sustainable energy solutions and agriculture,'' the report said.

However, there have been incidents of friction with local people at times due to ill-treatment of local employees and import of Chinese workers by some companies.

On Thursday, Chinese state owned enterprises operating in Africa including State Development Bank, the China-Africa development fund and China Non-Ferrous Metals Group, signed a declaration of social responsibility pledging to operate more responsibly and respect local customs, among other measures.