Angolan President Jose Eduardo dos Santos headed on Monday for his first official visit to China in seven years as his country, which is Africa's second largest oil producer, struggles with falling oil prices.

Dos Santos, who has ruled since 1979, only makes rare trips abroad from the former Portuguese colony, which remains one of the world's poorest countries despite its natural resources.

Dos Santos was invited for a three-day visit to China by President Xi Jinping, reported the government daily Jornal de Angola, adding the stopover would seek to bring a "new impetus" to relations.

Beijing has extended nearly $15 billion (13.4 billion euros) of credit to Angola since 2004, including help to finance major infrastructure projects such roads, rail lines and even new cities.

Angola draws about 70 percent of its income from oil, and falling prices have hit government revenue hard.

The country saw a decade of strong growth after the civil war ended in 2002, with development boosted by oil reserves. The government was also courted by China, the United States and Europe.

Dos Santos could seek new credit from Beijing, according to reports in the Portuguese press.

Official figures say that about 54 percent of Angolans live on less than two dollars a day.