Hundreds of protesters gathered in central Tunis on Saturday to demonstrate against a referendum to be held on Monday on a new constitution that they reject as illegal.
President Kais Saied published the draft constitution, giving himself far more powers, reducing the role of the parliament and judiciary, and removing most checks on his power, less than a month ago.
The referendum is the latest move in what his foes call a march to one-man rule since he moved against the elected parliament a year ago, replacing the government and moving to rule by decree in what critics call a coup.
"Shut down the coup!", "Stop autocratic rule!" shouted the protesters on Habib Bourguiba Avenue, the main street in central Tunis.
"The Tunisian people will deal a major blow to Saied on the day of the illegal referendum and will prove to him that it is not interested in his populist path," said Nejib Chebbi, the head of the anti-referendum coalition.
Saturday's protest was organised by the coalition, which includes activist group Citizens Against the Coup and Ennahda, an Islamist party that was the biggest in the dissolved parliament.
A large number of police stood along the avenue but there were no initial signs of violence.
During a separate protest on Friday evening by civil society groups and smaller political parties, police used sticks and pepper spray to disperse demonstrators, arresting several of them.
Divisions among the political parties and civil society organisations criticising Saied's moves has made it harder for the opposition to form a clear stance against him and mobilise street protests.
Saied's moves against the parliament last July came after years of political paralysis and economic stagnation and appeared to have widespread support.
However, there has been little sign of public enthusiasm for his referendum, with only limited numbers of people attending rallies to support it.
Many Tunisians, when asked about the political turmoil, point instead to a looming economic crisis as the most urgent issue facing the country.
(Reporting by Tarek Amara, writing by Angus McDowall, editing by Angus MacSwan)