U.N. Secretary-General Ban Ki-moon is appealing for calm in Senegal, where riot police clashed with protesters demanding President Abdoulaye Wade not run for a third term.

In a statement late Tuesday, Mr. Ban urged all sides to refrain from violence and “pursue peaceful means to resolve electoral grievances.”

Thousands of Senegalese, mostly young people, staged what was to be a peaceful demonstration Tuesday in the capital of Dakar. But, by nightfall, protests had turned violent as students threw stones at police and burned tires and riot troops responded.

Witnesses and officials say a 30-year-old student died after being run over by a truck during the protests. Police deny the incident involved a police vehicle.

Protesters were criticizing last week's high court ruling that cleared the 85-year-old president to seek a third term. A constitutional amendment limits presidents to just two terms, but Mr. Wade argues that he was elected before the amendment took effect.

The court ruling last Friday sparked riots that killed three people in the West African country.

The protesters say Mr. Wade is attempting a “constitutional coup d'etat.” Many protesters, including Bibi Camera, say a third term by Mr. Wade will make the country ungovernable.

“I am here because of our president. He is taking us for a ride. We don't want him anymore. If he doesn't listen, we will try to take him out of the palace because we are so sick of it.”

On Monday, U.S. Deputy Secretary of State William Burns said President Wade's decision to run for another term may undermine Senegal's “spirit of democracy” and could threaten its long record of political stability.