Bangladeshi police opened fire on attackers, shooting dead four people after demonstrations against the building of power plants on Monday.
A thousand villagers gathered in Gandamara in order to protest the $2.4 billion project backed by two Chinese companies.
According to the villagers, the protests were peaceful but local authorities had banned demonstrations. Police opened fire on the protesters as they tried to disperse them.
"We've filed cases against around 3,200 people for the violence. We've identified 57 of them but the rest are unnamed," local police chief Swapan Kumar told Agence France Presse.
According to Kumar, people do not want power plants to be built near their homes in fear that pollution would damage the environment and force them to leave the area.
People had been protesting in a good manner for days until the S. Alam Group, the Bangladeshi company behind the project, began levelling farmland in preparation for building the plants.
"Police will now use their power indiscriminately against any villager who speaks against the plants," a school teacher who lives in the village told AFP by phone on condition of anonymity.
Villagers organised more demonstrations against the plant on Tuesday, calling for justice for those who were killed.
According to local media reports, two coal-fired power with the capacity to produce 1,224 megawatts are being built.