Polls opened on Saturday in Gabon in a key vote that will see the nation decide whether President Ali Bongo will remain in office or be unseated by career diplomat John Ping, AFP journalists said.

In the working class district of Rio in the capital Libreville, a polling station set up at a school opened shortly before 8:00 am (0700 GMT) -- about an hour after the scheduled opening time.

Elsewhere in the capital, voting had not yet started at several polling stations.