Trade between China and African countries is estimated to be US$40 billion last year, according to Foreign Ministry statistics. Some 750 Chinese enterprises have invested a total of US$1 billion in the continent.

Hu said a joint declaration laying out specific measures to intensify Sino-African co-operation would be issued at the China-Africa Co-operation Forum summit to be held in Beijing in November.

Nigeria's Minister of State for Petroleum Edmund Daukoru said yesterday that the Sino-Nigerian agreement "is a formalization of the four oil block contracts, which include the maintenance and management of the Kaduna refinery and setting up a power generation station."

In exchange, China will grant Nigeria 40 million yuan (US$5 million) for infrastructure construction and 5 million yuan (US$624,000) for anti-malaria drugs, training for Nigerians to control malaria and bird flu, and co-operation in technology, according to other agreements signed the same day.

Last week, China's top offshore oil and gas producer, China National Offshore Oil Corp Ltd, completed a deal to buy a stake in a Nigerian oil-mining licence its biggest overseas acquisition.

"The main purpose of my visit is to deepen the Chinese-Nigerian relationship and strengthen the partnership both politically and economically," Hu said at the signing ceremony with Obasanjo.

Nigeria is the largest oil producer in Africa and the world's sixth-biggest exporter.

During talks between the two leaders before the signing, Hu proposed to expand partnerships in areas such as agriculture, energy, electricity, infrastructure construction, telecommunications and satellite technology.

Obasanjo said Nigeria welcomes more investments from China; and spoke highly of Beijing's policy of establishing industry in his country rather than the wholesale export of finished products.

Analysts said the oil deal was a good fit for both countries.

"China is an emerging world economy; she needs oil," former Nigerian foreign minister Bolaji Akinyemi said. "Nigeria needs as much investment as possible and to diversify the sources of its income."

Sino-Nigerian trade volume was US$2.83 billion last year, up 29.6 per cent from 2004, according to Foreign Ministry statistics.

China also has major investments in Nigeria's fast-growing telecoms industry and has found a ready market for textiles and other finished goods.

"Stronger ties between China and Nigeria are long overdue," said Wang Yusheng, former Chinese ambassador to Nigeria. "Many Chinese do business there and contribute a lot to the regional development."

Hu is scheduled to arrive in Kenya today on a state visit, the last stop of his five-nation tour, which has also taken him to the United States, Saudi Arabia and Morocco.