Africa's longest-serving ruler, President Omar Bongo Ondimba of Gabon, is reported to have died aged 73. He was being treated for an illness in a Spanish clinic.
Mr Bongo led the former French colony in west-central Africa since 1967.
Last month he suspended his functions as head of state for the first time since taking power.
French Defence Minister Herve Morin said on Sunday he was "a great figure of Africa" and a "man who had influence."
The president's wife, Edith Lucie Bongo Odimba, daughter of Congo President Nguesso, died in Morocco in March at the age of 45 after a long illness.