Senate President Rose Francine Rogombe is Gabon's new interim head of state, following Monday's death of long-time leader Omar Bongo. She is expected to organize new elections by the end of July.
Acting President Rogombe took the oath of office in Libreville's first change of power in more than 40 years.
Before an audience of judges, lawmakers, foreign diplomats, and government officials, Ms. Rogombe swore to devote all her strength to the good of the Gabonese people, to promote the nation's well-being and protect it from harm, and to defend the constitution.
The 66-year-old, ruling-party ally of the late president is a lawyer who served as deputy minister for human rights before becoming the first woman to lead Gabon's Senate.
She now holds most of the powers of an elected president, except for the authority to call a referendum or dissolve parliament. Her chief task is organizing new elections within 45 days.
Among potential candidates for that vote are Vice President Didjob Divungi Di Ndinge, the late president's son Defense Minister Ali Ben Bongo, and the defense minister's brother-in-law Foreign Minister Paul Toungui.
President Bongo died Monday in a Spanish clinic at the age of 73. He was Africa's longest-serving head of state, having taken power in 1967 following the death of Gabon's first president, Leon M'ba.
Mr. Bongo was one of three African leaders investigated by a French judge for embezzling public funds. The anti-corruption group Transparency International says more than 30 Bongo family properties in France, worth nearly $200-million could not have been purchased on his state salary alone.
President Bongo denied wrongdoing. With his death, Transparency International says it will continue its case against President Bongo's father-in-law, Congolese President Denis Sassou N'Guesso and the President of Equatorial Guinea, Teodoro Obiang Mbasogo.
President Bongo's body is expected to arrive Thursday in Libreville for military honors, before lying in state at the presidential palace.
Funeral services in the capital are scheduled for Tuesday with a private burial in his home region later next week.
Gabon's borders have reopened and Defense Minister Bongo says there will be no curfew, though bars and nightclubs in Libreville remain closed.