The majority of people arriving at a long-running anti-fracking protest are there to "disrupt and intimidate" the local community and "antagonise police", a police chief has said.
More than 80 people have been arrested at a drilling site in Barton Moss on the outskirts of Salford, Greater Manchester, with the figure rising "with each day of deliveries", police said.
Of the 82 people held, 62 are from outside the Greater Manchester area and many are from the south of England, according to Greater Manchester Police (GMP).
A number of those detained had been arrested previously at Barton Moss or other protest sites, the force said.
Chief Superintendent Mark Roberts said: "At the start of this protest the majority of protesters were peaceful and law-abiding but over the past couple of weeks local residents and officers have seen a distinct change to this.
"It now seems that the majority of people who are arriving at the site are not there to protest against fracking but are there to disrupt and intimidate the local community and to antagonise police."
Mr Roberts said the force had recorded offences of a ssault, damage, harassment of residents and workers, a flare fired at the police helicopter and threats to kill.
"I attended a residents' meeting last week and people there were close to tears and have had enough of this daily disruption to their lives," he continued.
"Locals, who initially supported the protesters, out walking their dogs and driving down Barton Moss Road have been approached by protesters in balaclavas and have been questioned by them, which has been extremely intimidating.
"We have seen a huge increase in the calls to police from that area and this is continuing.
"Officers are verbally abused on a daily basis, one has even been spat at and another officer required stitches to his hand after trying to get a protester down from a fence.
"The police are there to do a job and that job is to facilitate peaceful protest and to balance the needs of all parties, the residents who live there, businesses who operate from there and the protesters themselves."
Since November around 60 tents and caravans have sprung up along the farm track leading to the site, between Barton Aerodrome and the M62.
Police have been called on a number of occasions and made arrests as protesters have attempted to stop lorries entering by erecting blockades such as a giant wind turbine blade and a bus.
Environmentalists claim there is indisputable evidence that fracking causes air and water pollution and leads to earth tremors. The Government and industry say it is safe and will create jobs.
Mr Roberts said police were at the protest "to ensure that everyone remains safe" and it was not up to GMP "who operates on this land and who has access to it".
He added: "We are increasingly seeing protesters trying to jump in front of HGVs or jump down from trees on top of moving lorries - it is only a matter of time before someone is seriously injured if they continue to act in a reckless manner.
"We are working very closely with many partner agencies to try and resolve this emerging threat and issue to try and reassure the local residents who feel intimidated in their own homes from people who have travelled from all parts of the country to set up camp in Barton Moss."
Energy company IGas was granted permission for exploratory gas drilling at the site and said it is seeking methane and shale gas but has no plans for fracking.
An anti-fracking campaign group has accused GMP of being "out of control" after what it claimed was a violent arrest of a protester at Barton Moss on Monday.
Sean O'Donnell shot a video of himself being apparently tackled to the ground after he was accused of obstructing a police officer, campaign group Frack Free Greater Manchester said.
Sarah Carmichael from FFGM said: "This is not the first incidence of police violence we have seen at Barton Moss. There have been many occasions that I thought more people might get injured.
"The police have been aggressive to anybody who walks down with the trucks.
"They shout and scream in people's ears and we have seen an 82-year-old woman forcibly removed from the protest on numerous occasions. They even threw another disabled man down a hill so they could snatch arrest a pregnant woman.
"I have witnessed them arrest people for no reason at all. Before IGas arrived here I always believed we could trust our police but Greater Manchester Police are absolutely out of control."
Protester Sasha Conway, who lives at the camp, claimed officers behaved "like aggressive thugs and bullies".
"If they are not pushing elderly and disabled people down the road they are raiding the camp stating that a flare has been fired at their helicopter, but are refusing to provide any proof other than fictional comments made on a website where users are not asked to register," he said.
"I have been on other protests and witnessed similar behaviour from the police before but many of the local residents who visit are really shocked.
"They cannot believe that the police force could be so heavy handed and act as if they are above the law."
Frack Free Greater Manchester said it is in talks with solicitors to pursue legal action against GMP on a number of counts.
Earlier this month GMP said the cost of the policing operation at Barton Moss stood at £330,000.
Fracking involves the fracturing of rock with a pressurised liquid to release shale gas, with potentially vast reserves untapped across swathes of the UK.