Burundi protests
Burundi descended into chaos when President Pierre Nkurunziza announced he would run for a third term, which the opposition described as 'unconstitutional'Reuters

Former UN secretary-general Kofi Annan has urged African leaders to step down when their mandated time is up to stop contributing to conflicts on the continent.

While Senegal's president Macky Sall has attempted to cut his time in office to set an example for other heads of state, a number of African leaders have amended or are trying to amend the constitution to prolong their time in office, from Paul Kagame in Rwanda to Yoweri Museveni, who has been at the helm in Uganda since 1986.

Three of Africa's longest-serving heads of state – Zimbabwe's president Robert Mugabe, Jose Eduardo dos Santos from Angola and Teodoro Obiang Nguema Mbasogo of Equatorial Guinea – have been in power over 35 years.

In the Democratic Republic of Congo (DRC), Joseph Kabila is taking a slippery path to a third term despite being constitutionally required to step down at the end of the year. Neighbouring Burundi, meanwhile, descended into chaos a year ago when Pierre Nkurunziza ran for a third term despite controversy over whether he was eligible to run for a third term in the top seat.

President Denis Sassou Nguesso of Congo-Brazzaville was re-elected in March after the country held a referendum on constitutional changes that allowed to stand for a third term.

'Constitutions and the rules of the game have to be respected'

"I think Africa has done well, by and large the coups have more or less ended, generals are remaining in their barracks, but we are creating situations which may bring them back," Annan, who is a Nobel laureate, said during the fifth Tana High-Level Forum on Security in Africa held in Bahir Dar, Ethiopia.

"If a leader doesn't want to leave office, if a leader stays on for too long, and elections are seen as being gamed to suit a leader and he stays term after term after term, the tendency may be the only way to get him out is through a coup or people taking to the streets," he said. "Neither approach can be seen as an alternative to democracy, to elections or to parliamentary rule. Constitutions and the rules of the game have to be respected."

DRC protest third term
A protester holds the constitution of the Democratic Republic of Congo locked with a padlock in BarumbuJunior D. Kannah/AFP/Getty Images

Annan, who previously told the African Union the group should not accept coup leaders among their midst, insisted financing the continent's institutions would be the way forward to resolve issues from within.

"We cannot always pass a hat around and insist we want to be sovereign, we want to be independent," the Ghanaian diplomat said. "We should lead and get others to support us – that support will be much more forthcoming when they see how serious and committed we are."

Ethiopian Prime Minister Hailemariam Desalegn, Faure Gnassingbe from Togo, Somalia's Hassan Sheikh Mohamoud and Sudan's Omar al Bashir attended the forum, described as a platform for current and former leaders to interact with key players to tackle contemporary issues facing the continent.

They were joined by former leaders including Nigeria's Olusegun Obasanjo, Thabo Mbeki of South Africa, Festus Mogae of Botswana, Joaquim Chissano of Mozambique, Pierre Buyoya of Burundi and Joyce Banda of Malawi.

"I think it is a very good idea that ex-leaders come together with current leaders to share experience and try to talk very frankly about the challenges facing the continent and also about our relations with the international community," Annan told the leaders.