About 2,000 protesters snaked through the capital today, calling on Martelly to resign and accusing him of corruption.
Before being dispersed by riot police and UN peacekeepers, some demonstrators closed John Brown Avenue by scattering rocks across the roadway.
An Associated Press photographer saw police detain at least 10 protesters. The police department's spokesman could not be immediately located for comment.
It was the third large anti-government protest in a week.
Several thousand demonstrators reportedly rallied Saturday in the northern city of Cap-Haitien. Demonstrators smashed car windows during a Monday march through Port-au-Prince.