A rally against power cuts and food shortages appeared to begin peacefully in the city of Moron late on Friday then turned violent in the early hours of Saturday morning, Invasor newspaper said.
Videos on social media showed a large fire and people throwing rocks through the windows of a building as voices shouted "liberty" in the background.
Reuters was able to verify the location of one video in Moron, which is on Cuba's northern coast about 400km east of the capital Havana near the tourist resort of Cayo Coco.
Checks showed it was recent, but could not pinpoint the exact date.
Cuba's government said that its interior ministry has opened an investigation into the case.
The United States has tightened the screws on Cuba since capturing Venezuelan President Nicolas Maduro - Cuba's most important foreign benefactor - in January.
US President Donald Trump cut off Venezuelan oil shipments to Cuba and threatened to slap tariffs on any country that sells oil to Cuba, piling pressure on an economy already struggling with shortages of food, fuel, electricity and medicine.
Trump has in recent weeks made a series of statements, saying Cuba was on the verge of collapse or eager to make a deal with the United States.
Cuban President Miguel Díaz-Canel said on Friday that he was holding talks with the US government to try to defuse the crisis.
Díaz-Canel said that no petroleum shipments have arrived in Cuba in the past three months, and blamed a US energy blockade for that.
He said that the island is running on a mixture of natural gas, solar power and thermoelectric plants.
Public protests, particularly violent ones, are exceedingly rare in Cuba.
Its 2019 constitution grants citizens the right to demonstrate but a law more specifically defining that right is stalled in the legislature, leaving those who take to the street in legal limbo.
"What initially began peacefully, and after an exchange with local authorities, turned into acts of vandalism against the headquarters of the Municipal Party Committee," the Invasor newspaper said.
"A smaller group of people stoned the entrance of the building and started a fire in the street with furniture from the reception area," it added.
Vandals targeted several other state-run establishments in the area, including a pharmacy and a government market, the report said.
In one video on social media, a gunshot is heard, and the camera pans to a person lying on the ground.
State media outlet Vanguardia de Cuba dismissed online reports that the person lying on the ground had been shot by police.
"The image circulating shows the scene of the protest but it's important for the public to know the truth: no one was injured by gunfire," Vanguardia de Cuba said on X.
"Media manipulation seeks to sow fear and confusion among our people. Let's not fall for provocations," it added.
State media said police had detained five people and one drunken participant fell over and was being treated for injuries in hospital.
Over the past week, several small groups of residents across Havana have banged pots in protest against extended blackouts.
Students on Monday staged a sit-in on the steps of the University of Havana after the government suspended in-person classes, blaming the US oil blockade.
Fuel shortages have vastly reduced public transportation, making it difficult if not impossible for teachers and students to get together for classes.
Moron was also the site of significant protests during anti-government riots on July 11, 2021, the largest since Fidel Castro's 1959 revolution.
with AP
