Police opened fire Tuesday on protesters demanding the closure of a south Indian copper plant, killing nine people, officials said. Dozens more people were reportedly injured.
The violence came amid months of protests against the Sterlite copper smelting plant in the town of Tuticorin, which demonstrators say has polluted the area's groundwater and put local fisheries at risk.
On Tuesday the demonstrations turned violent, with media reports and officials saying protesters began rampaging through the town, pelting police with stones, overturning cars and setting fires.
"The police had to take action under unavoidable circumstances to protect public life and property," said K. Palaniswami, the top official in Tamil Nadu state.
Palaniswami ordered an inquiry into the shooting and announced payments of 100,000 rupees (about $1,500) to the families of those who had been killed.
Security personnel were rushed to the area amid fears that the violence could spread.
Politicians called for peace.
"At this critical hour, I appeal to all sections of society to be calm and help in maintaining the peace in the state," Tamil Nadu Gov. Banwarilal Purohit said in a statement.
The copper plant, owned by a branch of Vedanta Ltd., has been a focus of protests since 2013, when a gas leak sickened dozens of people. The plant was shut in late March by pollution regulators, though it could re-open as early as June 6.
Opposition politicians blasted the government's violent response to the protests.