By Diadie Ba and Pascal Fletcher
DAKAR (Reuters) - Senegal's President Abdoulaye Wade faces re-election on Sunday, having defied opposition efforts to block him from standing and warnings that his candidacy risked destabilizing the usually tranquil West African state.
Overshadowing voting is a row over whether the octogenarian leader should be able to run for a third term. It has sparked violent street protests and a stream of warnings that Senegal's reputation as an established democracy now hangs in the balance.
Foreign powers and diplomats issued last minute appeals for calm and a transparent vote, and a top African mediator failed to secure an agreement between Wade and his rivals over a shortened term for the incumbent if he won.
"We are closely watching the development of the situation. I have been concerned about what is happening there," United Nations Secretary General Ban Ki-moon told journalists on Saturday during a visit to Zambia when asked about Senegal.
"I sincerely hope that this election will be held peacefully in a credible, open and transparent manner so that the will of the people will be fully respected," he said.
The former French colony has long enjoyed a reputation of stability and held a series of successful elections in an otherwise often turbulent region since independence in 1960.
But the run-up to Sunday's poll has been tense, with Wade's rivals saying he should not be allowed to stand due to term limits but the incumbent saying restrictions were brought in after he took power, so his first term did not count.
Six people have been killed in election-related violence so far. Washington has said his decision to run again was regrettable while Paris has said it was time for Senegal's younger generation to take power.
But Wade, a veteran of years in opposition before he took power in 2000, has mocked rivals at home for failing to mobilize a significant challenge and batted critics from abroad.
"This is Africa. Yes, I am old but I am physically well," Wade told French weekly Sunday newspaper Le Journal du Dimanche.
"My age has become an advantage. I am president and father of the nation. This is what the Europeans do not understand."
Some 5.1 million Senegalese are eligible to vote for the 14 contenders, which include main rivals Macky Sall and Idrissa Seck, both former prime ministers who had served under Wade.
Days before voting took place, the European Union observer mission warned that 500,000 voters, nearly 9 percent of the electorate, were yet to collect their voter card.
Amid the rows over Wade's candidacy, warnings of further violence and talks over possibly limiting Wade's time in power if he won, some Senegalese retained hope in the process.
"My weapon is my voter card," said Ahmed Ndiaye, a 22 year-old carpenter in Dakar. "I will use it and I hope that it will rid us of this old president."
(Additional reporting by Chris Mfula in Lusaka and Catherine Bremer in Paris; Writing by David Lewis; Editing by Michael Roddy)