At least six persons were injured when striking workers of CPI(M)'s labour wing CITU clashed with members of Trinamool Congres-affiliated union near the Haldia Petrochemicals Ltd (HPL) supermax project site in East Midnapore district.

Police said the CITU workers were picketing near the plant site in support of their indefinite strike, which began yesterday, when some members of INTTUC (Indian National Trinamool Trade Union Congress) tried to forcibly enter the HPL complex.

A clash soon broke out leaving at least six persons, reportedly from both sides, injured, police said adding the injured were taken to local hospital.

A police force later lathicharged at Durgachak Primary Health Centre, some one km away from the spot, when they were allegedly prevented from apprehending some of those allegedly involved in the clash.

Some people, including a nurse, were injured in the melee at the health centre, police said.

The Trinamool Congress blocked roads at Mahisadal, Contai, Ramnagar and other parts of East Midnapore in protest against the alleged attack on its members but the CPI(M) blamed TC for "provocative" acts.

Work continued to be affected at the petrochem major's Rs 1,200 crore ambitious project site as a result, CITU sources claimed. The company management could not be contacted.