FACTBOX: Africa's longest-serving leaders
(Reuters) - The official birthday party of Zimbabwean President Robert Mugabe, one of Africa's oldest and longest-ruling leaders was celebrated at a big rally Saturday.
Here are some details on the longest-serving leaders in the African Union.
* ANGOLA - Eduardo Dos Santos (66)
Dos Santos assumed the presidency of the mineral-rich country in 1979, four years into a civil war with UNITA rebels that finally ended in 2002.
* CAMEROON - President Paul Biya (76)
Biya took over in 1982 from President Ahmadou Ahidjo and won re-election for another seven-year term in October 2004.
* CONGO REPUBLIC - President Denis Sassou Nguesso (65**)
Sassou Nguesso seized power in a 1979 coup but then lost the country's first multi-party elections in 1992 to scientist Pascal Lissouba. He regained the presidency in 1997 after a brief but bloody civil war and was re-elected in 2004 for a further seven-year term.
* EGYPT - Hosni Mubarak (80)
Mubarak became president of the Arab world's most populous country after the 1981 assassination of President Anwar Sadat by Muslim militants angered by his foreign policy and domestic repression. Mubarak was sworn in as president in September 2005 for a fifth six-year term.
* GABON - President Omar Bongo (73)
Bongo, born on December 30 1935, came to power in November 1967. The veteran leader has changed the constitution to remove any limits on presidential terms. Bongo, who has ruled the oil producing country since 1967, won 79.2 percent of the vote in November 2005 elections, comfortably ahead of his four challengers.
* LIBYA - Muammar Gaddafi (66**)
Gaddafi seized power in a bloodless military coup in 1969 and oversaw the rapid development of his poverty-stricken country. Previously known for little more than oil wells and deserts and regarded as an international outcast by the West, Libya pledged to abandon its weapons of mass destruction programs, drawing praise from Washington and London.
* SWAZILAND - King Mswati III (40)
King Mswati is sub-Saharan Africa's last absolute monarch and was crowned in April 1987. Political parties have been banned in landlocked Swaziland since 1973. The king introduced a new constitution in 2006, but the ban on political parties remained. The king has kept control over the legislature in a country, plagued by food shortages and one of the world's highest HIV/AIDS prevalence rates.
* TUNISIA - President Zine al-Abidine Ben Ali (72)
Ben Ali has overseen successful economic reforms and crushed an Islamic fundamentalist opposition since he came to power 21 years ago in 1987. Supporters of Ben Ali have predicted he will seek another mandate when his latest term ends in 2009. Commentators say he can take credit for making Tunisia the healthiest and best educated nation in north Africa.
* UGANDA - President Yoweri Museveni (64**)
Museveni declared himself president in January 1986 when he seized Kampala after a five-year guerrilla struggle. Museveni banned multi-party politics shortly afterwards. One of Africa's longest serving leaders, Museveni looks likely to win re-election in 2011 with little challenge to his rule.
* ZIMBABWE - President Robert Mugabe (85)
Mugabe became Zimbabwe's prime minister in 1980 after independence elections. The former Marxist guerrilla became president in 1987 and has held fast to power despite a deep financial and health crisis that has almost ruined the country he fought so hard to free.
NOTE: **Age not precisely known.