Police are investigating an alleged assault at the Preston New Road fracking site.
Protesters say a man was punched and put in a headlock, while another had his leg trapped in a car door and others were pushed into the road on Tuesday at 5.30am.
Ellen Gibson, from Reclaim the Power said: “The brutality by Cuadrilla’s security team represents a totally disproportionate, violent and unnecessary response to the ongoing peaceful protests at Preston New Road.
“While security guards may be allowed to use ‘reasonable force’ to eject someone from private property; punching demonstrators in the face while pinning them to the ground on a public road amounts to assault.”
But shale gas exploration company Cuadrilla denied that anything illegal had occurred and said their security team faced harassment.
Francis Egan, from Cuadrilla said: “An incident occurred during which there was an altercation between a protester and a member of our security team.
"The team are used to dealing with a number of protesters, most of them peaceful, on a daily basis. However on this occasion, the protester became aggressive.
"We understand that the protester was appropriately restrained and then handed over to Police, who were present throughout the brief incident. The matter is now in their hands and we will assist them in any investigation which follows.
"Since the incident, the employee concerned and his family have been subjected to unacceptable harassment and intimidation, which is also under investigation by the police."
A police spokesman said: “A complaint has been made and we are investigating.”