The police said three persons were injured at Parashkul colliery in a clash this morning.
The injured TC workers were admitted to Bidhannagar Hospital in Durgapur.
Trinamool Congress leader and state Agriculture Minister Malaya Ghatak alleged that CPI-M cadre led by Vijay Singh hurled bombs at the Trinamool Congress supporters when they were getting ready to attend the rally to be addressed by Mamata Banerjee at Polo Ground in Asansol.
Meanwhile, local CPI-M MLA Gouranga Chatterjee said the incident was a fall-out of a dispute between TC workers and locals over opening of open cast coal mine.
Firearms and cartridges were found from the area during a house-to-house search later in the day, the police said.
Four persons, including a woman were arrested, officials said.
