Three supporters of India’s ruling right-wing party and another from a rival regional party have been killed in a gun battle in West Bengal state, police and a local politician said Sunday.

The conflict in the North 24 Parganas district of the state involves members of the national ruling Bharatiya Janata Party (BJP) and the All India Trinamool Congress (TMC), which dominates the state’s legislature and is represented in the national parliament.

Of the four people killed, three belonged to the BJP and one to the TMC, according to the Hindu.

The BJP said Trinamool supporters attacked their activists after a scuffle over party flags, shooting indiscriminately. Mukul Roy, a state leader of the party, said the TMC leadership was “indulging in a reign of terror” in West Bengal.

The TMC claimed that armed BJP activists attacked their members first, killing one person and apparently triggering retaliation. Local police have not immediately issued a statement about the conflict.