Africa is home to more than half of the top 20 longest-serving political leaders in the world.

They've flouted election laws and splashed tax-payer cash on expensive hotels while clinging desperately to power.

Robert Mugabe has ruled Zimbabwe for 37 years but that's not long enough to put him at the top of the list.

Here are some other African leaders who've shown serious staying power.

Teodoro Obiang Nguema Mbasogo — 38 years

President Teodoro Obiang Nguema Mbasogo has been repeatedly returned to power in elections condemned as fraudulent.

The leader of the tiny oil-rich nation of Equatorial Guinea became the longest-serving president in the world in 2011, following the death of Libya's leader of 42 years, Moammar Gaddafi.

Mr Obiang swept to power in 1979 when he ousted his uncle, Francisco Macias Nguema, in a bloody military coup.

He's been re-elected every seven years following polls that internationals observers have repeatedly condemned as fraudulent.

During his rule, parts of the population have prospered, with the country boasting one of the highest per-capita incomes on the continent.

But, according to Human Rights Watch, roughly half the population lacks access to potable water, while life expectancy and infant mortality rates are below the sub-Saharan average.

Meanwhile, Mr Obiang and his family have amassed considerable personal wealth. Last month, his son was sentenced to a three-year suspended jail term for corruption by a French court.
Paul Biya - 35 years

Cameroon's 'lion man' Paul Biya has been accused of rigging elections.

Cameroon's President had his first taste of political power as prime minister in 1975 before assuming the presidency seven years later.

Often described as an "absentee landlord" because of his frequent holidays abroad, Mr Biya has been accused of rigging elections in his favour and allowing the constitution to be changed to further his rule.

He's survived several coup attempts and he adopted the nickname "lion man" in 1990 after Cameroon's national football team, the Indomitable Lions, reached the quarter-finals of the World Cup.

Earlier this year, dozens of people were killed and hundreds arrested during a crackdown on anti-government protests in the country's English-speaking regions.

Opposition leader Aboubakar Siddiki was sentenced to 25 years in prison by a military court last month, in a trial Amnesty International described as politically motivated.
Denis Sassou Nguesso - 33 years

Human rights abuses and corruption have reportedly been widespread under Sassou Nguess.

Sassou Nguesso has had two separate stints in the top job in the Republic of the Congo. He was president from 1979 to 1992 before returning to power in 1997 during the country's second civil war.

Like many others, he's courted controversy.

Violence and vote-rigging have become common features of his election campaigns, while human rights abuses and corruption have reportedly been widespread during his time in office.

In September 2006, during the United Nations General Assembly, his entourage reportedly racked up a hotel and room-service bill of about $230,000 — more than the amount of humanitarian aid the country received from Britain the same year.

The following year, Global Witness published documents that appeared to show his son, Denis Christel Sassou Nguesso, had spent hundreds of thousands of dollars of oil revenue on shopping sprees in Paris and Dubai.
Yoweri Museveni - 31 years

A constitutional amendment allows Yoweri Museveni an unlimited presidential term.

Coming to power as President of Uganda in 1986, Mr Museveni was initially celebrated as part of a new generation of democratic African leaders.

Uganda has experienced a period of relative stability and economic growth during his time in office, following the devastating rule of Idi Amin.

But the suppression of political opposition remains a problem, according to human rights groups.

In 2005, a constitutional amendment scrapped presidential term limits, enabling him to rule unchallenged.

An evangelical Christian, he's well known in the West for his decision to criminalise homosexuality in early 2014.
Omar al-Bashir - 28 years

Omar al-Bashir is wanted for war crimes by the International Criminal Court.

President of a country racked by decades of violence and civil war, Omar al-Bashir was a brigadier in Sudan's army when he came to power in a 1989 military coup against democratically elected prime minister Sadiq al-Mahdi.

He's has been accused by the International Criminal Court of organising war crimes and crimes against humanity in Darfur.

Despite an international arrest warrant, he won elections in 2010 and 2015, which were marred by controversy and opposition boycotts.

He faces an international travel ban but has visited Egypt, Saudi Arabia and South Africa nonetheless.