The presidents of China and Angola signed a series of agreements Wednesday as the oil rich African nation sought greater Chinese participation in its energy and infrastructure development.

"I would like to thank the Chinese side for aid and help," Angolan President Jose Eduardo dos Santos said at the beginning of talks with his Chinese host President Hu Jintao.

"In modern history the Chinese government and people have provided aid and help to Angola. This help has come over many different time periods," state radio quoted him as saying.

Following talks, the two leaders oversaw the signing of a cooperation framework agreement, a pact on economic and technical cooperation and an aviation transport agreement, Chinese foreign ministry officials said.

China has been a key financial partner for Angola as it rebuilds its infrastructure after decades of civil war.

While loans from the Asian giant are officially believed to exceed four billion dollars (three million euros), a government source told AFP it was closer to seven billion dollars.

Much of the cash is oil-backed and Angola is now China's largest supplier of crude oil. Around 40,000 Angolan visas were issued to Chinese workers last year.

"The president is making this visit to appeal for more financial investment from China," a senior Angolan official told AFP ahead of the visit.

"The water sector needs a lot of investment and this is the next big area the government is working on and it hopes the Chinese will be able to help with the financing."

On Thursday dos Santos will meet with Prime Minister Wen Jiabao and China's parliamentary head, the foreign ministry said.

Dos Santos is accompanied by Foreign Minister Assuncao dos Anjos, Finance Minister Severim de Morais, and Transport Minister Augusto Tomas, the Angolan state news agency ANGOP reported.

The trip is his second to China in five months and comes as the west African nation is being forced to re-evaluate its budget following the drop in oil prices.