Jean Ping, the main challenger to the incumbent Omar Bongo on Sunday said he had won the presidential election in Gabon.

Official results of Saturday's vote are due out on Tuesday.

"I have been elected. I am waiting for the outgoing president to call to congratulate me," Ping told journalists and his supporters in Libreville.

The central African country's interior minister has repeatedly stated that only results released by the electoral commission and confirmed by his ministry are valid.