AFRICA'S POPULATION: 1BN Central Africa: 125.7m East Africa: 318.8m North Africa: 209.4m West Africa 298.6m Source: UNPF, State of the World Report 2009

The number of people in Africa has passed the one billion mark, the UN Population Fund says in a report.

UNPF's Executive Director Thoraya Obeid told the BBC that the annual figures showed the continent's population had doubled in the last 27 years.

"Africa countries are all growing fast... because there is large number of women who have no access to planning their families," she said.

The populations of Nigeria and Uganda were growing the fastest, she said.

"It's an African phenomenon of a large growing population and a large percentage of young people in the population," she told the BBC's Network Africa programme.

In its State of the World Report, the UNPF says the world's population currently stands at about 6.8 billion.

Africa's population is estimated to reach 1.9 billion by 2050, it says.