Three supporters of India ‘s ruling right-wing party and another from a rival party have been killed in a gun battle in West Bengal State.

At least 18 others were wounded in the clashes which broke out on Saturday in the state that has been on edge since Prime Minister Narendra Modi’s Bharatiya Janata Party (BJP ) launched an aggressive campaign to win the parliamentary seats last year.

Local BJP leader, Mukul Roy tweeted that three BJP workers were shot dead in Sandeshkhali, West Bengal after clashes broke out over the hoisting of BJP flags and the putting up of posters.

BJP’s General secretary in West Bengal, Sayantan Basu said the opposition supporters tried to throw away their party flags and posters and when they protested, their workers were shot from point-blank range.

State’s Minister Jyotipriyo Mullick, who belongs to the Trinamool Congress party said one of their party supporters was also ‘hacked and shot dead by BJP workers’.

“When he was on his way to attend a party meeting, he was hacked at first. When he managed to free himself, he was shot dead,” Mullick told reporters in Sandeshkhali.

Rival supporters have regularly clashed in the politically volatile state where the BJP won 18 seats, up from the two it managed in 2014, en route to its massive nationwide win last month.

Modi’s party won 303 seats in the national parliament, increasing its previous tally of 282 seats in 2014.

The Trinamool Congress, which has its stronghold in West Bengal and is led by the firebrand Mamata Banerjee has also accused the BJP of fomenting trouble in the state.

West Bengal has witnessed some of the most violent feuds between rival parties. Last month, a BJP supporter was shot dead in Kolkata and a car belonging to a Trinamool member was pelted with rocks.

Last year, a BJP worker was killed and his body was hanged from a tree.