NEW DELHI (Reuters) - At least nine people were killed in India’s Tamil Nadu state on Tuesday when police fired at violent protesters calling for the closure of a copper smelter run by Vedanta Resources, authorities said.

The state’s chief minister, Edappadi K. Palaniswami, said police had been forced to act after the protests turned violent, and that nine people had been killed. The state’s governor put the death toll at 11.

The head of the national opposition Congress party, Rahul Gandhi, condemned the use of lethal force, calling it “a brutal example of state-sponsored terrorism”.

Residents of the port city of Thootukudi, located at the tip of the Indian subcontinent, and environmentalists have been demonstrating for more than three months against the copper plant, one of India’s biggest, alleging that it is a major source of pollution and a risk to fisheries.

On Tuesday, a crowd waving black flags stormed the district government headquarters and an apartment block for Vedanta employees, a company official said, declining to be named for fear of being targeted.

Protesters set vehicles on fire and threw stones at police, Palaniswami said in a statement.

He said police had been forced to act “since protesters disregarded a curfew, acted against the advice of police”, and indulged in violence.

Women shout slogans during a protest against the government and police forces after at least nine people were killed when police fired at protesters calling for the closure of a Vedanta Resources-controlled copper smelter in Thootukudi, in southern Indian state of Tamil Nadu, in Chennai, India, May 22, 2018. REUTERS/P.Ravikumar

“MURDERED FOR PROTESTING”

Gandhi tweeted: “The gunning down by the police of nine people in ... Tamil Nadu, is a brutal example of state-sponsored terrorism. These citizens were murdered for protesting against injustice. My thoughts & prayers are with the families of these martyrs and the injured.”

Local television showed police trying to disperse the crowd with tear gas and a policeman firing shots from the top of a van. Smoke rose from several parts of the city.

State Minister D. Jayakumar said in a televised address that it had been “unavoidable” for police to fire on protesters.

The plant, which can produce 400,000 tonnes of copper a year, has been shut for more than 50 days and will remain closed until at least June 6 because the local pollution regulator has said it is not complying with environmental rules.

Environmental activists and some local politicians want the government to shut the plant permanently.

“The inaction of the government has led to the people’s protests, and police resorting to firing to control it. Action should be taken to shut down the plant immediately to address this issue,” M.K. Stalin, leader of the main opposition group in Tamil Nadu, Dravida Munnetra Kazhagam, said in a Facebook post.

Vedanta says the protests are based on “false allegations”, and that it plans to double capacity at the smelter to 800,000 tonnes per year.

“We would like to restart the plant as soon as possible, in a peaceful manner,” P. Ramnath, chief executive of Vedanta Ltd’s copper business, told Reuters.

The plant was shut for more than two months in 2013 by an environmental court after residents complained about emissions.