Angola's president says the state oil company has not been able to pay revenues into the country's budget since January and that low oil prices have caused a lack of foreign currency and made managing affairs "extremely complicated."

Jose Eduardo dos Santos spoke Wednesday on the sidelines of an economic meeting of his Council of Ministers. His comments were reported by the news website Rede Angola.

Angola is Africa's largest oil producer, and falling oil prices have hit hard. The Organization of the Petroleum Exporting Countries says oil production makes up about 45 percent of Angola's gross domestic product and more than 95 percent of its exports.

Dos Santos this month appointed his daughter, Isabel, the head of the state oil company, Sonangol.