Tunisian police used pepper spray and sticks on Friday to disperse dozens of protesters who were trying to march towards the Interior Ministry during a demonstration against a draft constitution expanding presidential powers.
The protesters, including leaders in political parties and civil society organisations, chanted "No to a dictator's constitution" and "Freedom, freedom... end the police state" as they gathered on the central Habib Bourguiba Avenue.
President Kais Saied has rewritten the democratic 2014 constitution and on Monday he will put it to a referendum that most political parties have said they will boycott.
Saied has amassed political powers since last year when he fired the prime minister, suspended parliament and moved to rule by decree saying he was saving Tunisia from years of political chaos.
He has promised to uphold rights and freedoms won in the 2011 revolution that brought democracy, but his critics say he is marching towards one-man rule and they fear a slide towards autocracy.
Friday's protesters included leading figures in Attayar party, Joumhouri party and the Workers' party. A Reuters journalist at the protest saw police arresting at least five demonstrators.
The biggest opposition party, the Islamist Ennahda, will hold a separate protest on Saturday.
Analysts say divisions among parties and activist groups opposing Saied have made it easier for him to advance his agenda.
(Reporting by Tarek Amara, writing by Angus McDowall; Editing by David Gregorio)
