Senegal's Constitutional Court on Friday ruled that President Abdoulaye Wade, 85, can seek a third term in office.
Witnesses said protesters erected barricades, burned tires and fought running battles with security forces in the streets of Dakar after the news was announced.
Wade, who has ruled Senegal for the past 11 years, was among 14 candidates that the court announced could contest the February 26 election. Among the notable omissions on the list was popular singer Youssou n'Dour.
Reports said the court ruled that n'Dour had not gathered the necessary 10,000 valid signatures backing his candidacy.
Wade's opponents say the constitution sets an upper limit of two terms for the presidency. Wade, who was elected in 2000 and 2007, has said his first term pre-dated the 2001 amendment setting the term limit.