The world's oldest head of state, Paul Biya, has extended his more than four-decade rule by securing an eighth term in Cameroon's presidential poll which his rival claimed to have won, the Constitutional Council announced Monday.

As President Paul Biya extends his four-decade rule, opposition leader Issa Tchiroma Bakary faces shrinking choices in a system seemingly designed never to change.

Official election results gave him an eighth term that, if completed, will last until he is 99. Mr. Biya is one of many leaders well over 70 across Africa, the world’s youngest continent.