•  France still an important player in west, central Africa
•  Some African leaders reluctant to relinquish power
•  Hollande vows to keep fighting militant groups in Africa

COTONOU: French President Francois Hollande urged African leaders on Thursday to respect their constitutional term limits amid concerns that some are prepared to risk political instability in order to cling to power.

Hollande was speaking a day after at least six people were killed in violent clashes in Burundi, where opposition parties are furious over the decision of President Pierre Nkurunziza to seek a third term, which they say is unconstitutional.

Burkina Faso's longtime ruler Blaise Compaore was toppled in a popular uprising last October after making a similar attempt to remain in power.

"We witnessed it again in Burkina Faso. Today in Burundi we are seeing the consequences. When these (constitutional) rules are not respected, are not shared, then there are risks and there are consequences," Hollande told reporters in Benin at the start of a two-day African visit.

Benin's President Thomas Boni Yayi has said he will not seek a third term next year.

Congo Republic's President Denis Sassou Nguesso, 71, has not yet said if he plans to seek another seven-year term. He called for a national dialogue this week, one subject of which would be potential constitutional changes lifting term limits and age restrictions.

France was the principal colonial power in West and Central Africa and still wields significant economic and political influence in the region, including playing a key role in the fight against Islamist insurgents there.

"France is thinking of its security, because what happens in Africa has consequences in Europe ... So by ensuring the fight against terrorism with our African friends, we are protecting ourselves," Hollande said, thanking Benin for its support.

France sent troops to drive al Qaeda-linked militants out of northern Mali in 2013 and has established an operation to take on Islamist fighters across West Africa's arid Sahel band.

Benin, meanwhile, has pledged to contribute troops to a regional force, also including Nigeria, Chad, Niger and Cameroon, against Nigeria's Boko Haram militant group.

Hollande also hopes this week to rally African support for efforts to tackle global climate change. Paris will host U.N. climate talks in December that the European Union hopes will result in a legally binding deal to curb global warming.

"The goal is, through the fight against global warming, to ensure that countries like Benin develop at a much faster pace," he said.

Hollande will also visit Angola and Cameroon on his tour. (Additional reporting and writing by Joe Bavier; Editing by Gareth Jones)