Senegal held a tightly-contested presidential run-off election Sunday between its 85-year-old president and a rival who has the backing of a dozen other opposition leaders.

Voters formed long lines in the capital, Dakar, for a poll that analysts say could threaten the stability of one of Africa's most peaceful democracies.

President Abdoulaye Wade is running for a controversial third term against former prime minister Macky Sall.

Senegal's constitution limits the president to two-terms and Mr. Wade's bid for a third mandate has sparked deadly riots.

International observers say Sunday's run-off election was generally orderly and peaceful, although police fired tear gas outside one polling station in the capital, Dakar. Police dispersed hundreds of Wade supporters just before the president arrived to cast his ballot at the station.

Supporters cheered for the incumbent in a scene that was very different from the initial poll on February 25, when bystanders booed Mr. Wade when he arrived to vote.

President Wade garnered 35 percent of the vote and Mr. Sall came in second with about 27 percent in the initial poll.

Since then, 12 other opposition leaders have backed Mr. Sall in his bid to unseat the incumbent.

President Wade has said he needs more time to finish projects, including construction of a new airport in Dakar. He also said he could run for a third term because constitutional term limits took effect after he was first elected. Critics have accused the president of focusing on infrastructure projects while ignoring the needs of the people.

Former prime minister Sall has promised to reform the government and to lower basic food costs.

“What we see until now is a calm and orderly election day where the polling stations opened at eight o'clock, where people are standing in line to vote in an orderly and calm way, dignified. I don't see much difficulty until now, although there is clearly high political tension because there is something at stake and that is normal.''

SIDI KONE, VOTER (french ) 1 act SAYING: (video slugged SENEGAL VOTING )

“I don't think there will be any problems because everything is checked and there are so many people supervising and checking today, it's exceptional. I am 74-years old but I've never seen a vote as we observed as this in Senegal before.'' ))