Senegalese voted Sunday in a run-off election in which the 85-year-old incumbent Abdoulaye Wade is fighting off a mass opposition effort to foil his controversial bid to stay in power for a third term.

Senegalese voted Sunday in a run-off election in which the 85-year-old incumbent Abdoulaye Wade is fighting off a mass opposition effort to foil his controversial bid to stay in power for a third term.

Having failed to deliver a crushing first-round victory a month ago, Wade faces a stiff challenge from his former prime minister Macky Sall, who has the full weight of the opposition behind him.

Long lines snaked outside voting stations as people waited to vote in the decider poll after two months of suspense which has seen the reputation of one of Africa's pioneer democracies put on the line amid deadly riots.

As a coup played out in neighboring Mali, EU election observers urged Senegal to prove its credentials as a strong democracy in a troubled region.

The elections commission noted several clashes between rival supporters during the election campaign, but it was calm compared with the run-up to the first-round vote in February, when near-daily riots left six dead.

Both candidates have declared they cannot lose, raising fears that the poll's outcome will inevitably be challenged.

Around the capital hundreds queued up to vote, raising hopes of a better turnout than in the first round when only 51 percent turned up.

While Wade came first in the February 26 vote with nearly 35 percent of the vote to his ex-protege's 26 percent, the octogenarian is in an uncomfortable position as Sall has secured the support of all the other candidates during the electoral campaign.

Wade has faced stiff rebukes from abroad with former colonial power France and  the United States urging him to retire as he pursued his controversial bid for a third term by circumventing a constitutional term limit.

Some 5.3 million voters are registered to cast their ballots in the run-off election, which will finish at 18:00 GMT under the gaze of 300 international observers.