Several government offices, schools and a police station were attacked to destroy voting material in Guinea ahead of a controversial constitutional referendum scheduled for Sunday.
The vote for a new constitution, due to take place on March 1 but delayed by Guinea's leader Alpha Conde, is seen by critics as an attempt by the president to extend his grip on power.
The government insists the vote is democratic.
Conde said Saturday he was sure the poll would take place peacefully, and added that he had followed the advice of fellow African leaders about cleaning up electoral rolls.
Voting would be "calm and serene," Conde said on Facebook. "It will take place in full transparency with absolute respect for democratic rules and republican customs."
Major African organisations "have made recommendations that were completely taken into account," he added.
Sunday's referendum was postponed last month by the president after international criticism over millions of unaccounted-for names on the electoral roll.
Officials now promise those names have been scrubbed, but doubt still lingers for the country's embattled opposition.
Police station, schools attacked
Protesters attacked several buildings and destroyed voting material overnight Friday into Saturday, several local officials told AFP.
A police station in the central Mamou region was targetted by attackers who "tore up (voter) lists and ransacked dozens of boxes containing electoral cards," an official told AFP Saturday.
Two public schools that were supposed to operate as polling stations were also burned, another local official said.
Several other administrative buildings in the north and southern part of the country were torched as well, sources said.
Supporters of the opposition FNDC party erected road barricades and burned tyres in the streets of Labe city in the north on Saturday, witnesses said.
Security forces were posted in front of public buildings, including the hospital and the governor's residence.
"Things are bubbling up all over the country," an official from the interior ministry said Saturday, speaking on condition of anonymity.
The government argues the proposed constitution will, among other things, codify gender equality in the West African state, and that holding a referendum is democratic.
But critics insist Conde is looking for a third term in office by using the new constitution to bypass two presidential term limits.
Since October, Guineans have taken part in sometimes violent mass protests against the possibility of a third term.
At least 31 protesters and one security officer have been killed in the unrest to date, according to an AFP tally.
The vote is taking place against a backdrop of unease over the spread of coronavirus, with two cases confirmed in Guinea so far, one of which has now been cured, the health ministry said.