Togo's security forces fired teargas on several thousand opposition supporters to disperse a rally in the capital Lome on Friday, injuring several people, organisers said.
The Let's Save Togo coalition of opposition and civil society groups has organised a series of recent rallies demanding major electoral reform and the resignation of President Faure Gnassingbe.
"We have recorded injuries. Some are currently in the hospital," said coalition member Pedro Amuzu.
Some youths set tyres on fire and attempted to set up barricades, but the security forces dispersed the march roughly 800 metres (2,600 feet) after its starting point in the Be area of Lome.
Protest organisers and the authorities had not agreed on a route for the march beforehand and security services have fired teargas in previous similar cases.
When the two sides have agreed a route, rallies have gone off without incident.
Friday's march was organised to mark the anniversary of a 1990 demonstration considered the first protest against the rule of general Gnassingbe Eyadema, the current president's father who ruled the small west African nation with an iron fist from 1967 until his death in 2005.
Parliamentary polls had been slated for this month, but they will almost certainly be delayed.