Senegal has banned political demonstrations in central Dakar ahead of protests planned to oppose President Abdoulaye Wade's re-election bid.
His plans to seek a third term in office have sparked widespread criticism.
Mr Wade dropped proposed changes to the country's constitution after huge demonstrations last month.
The ban has been criticised but protests set for Saturday have been moved out of the capital's centre.
Human rights activist Alioune Tine, a leader of the June 23 Movement (M23) behind the demonstrations, said the switch was being done to "appease" the situation, reports the AFP news agency.
The march had been due to take place in Independence Square in central Dakar, which is near the presidential palace.
Announcing the ban "for reasons of security", Interior Minister Ousmane Ngom said political protests were banned in much of central Dakar, citing several government buildings.
The June 23 Movement was formed after last month's countrywide protests - the most violent protests of Mr Wade's 11-year rule.
They led Mr Wade to drop his plans to reduce the proportion of votes needed to win a presidential election, and avoid a run-off, from more than 50% to 25%.
He had also wanted to create an elected post of vice-president.
Mr Wade's critics accused him of planning to use the new post to hand power to his son, already a powerful minister.
Both men have denied the claims.
Mr Wade, a veteran opposition leader, first came to power in democratic polls in 2000.