Some anti-hunt campaigners are targeting the homes of huntsmen they think are breaking the hunting ban, a senior police officer has said.
Mr Yeo said only five investigations into illegal hunts were ongoing
Sussex's Assistant Chief Constable Nigel Yeo said he knew of cases of houses and kennels being targeted.
These had happened since the ban came into force in February, Mr Yeo told the Association of Chief Police Officers' annual conference on Tuesday.
He said he feared the conflict could escalate when the hunting season began.
The traditional date for the new hunting season to open is in September.
Speaking at the conference in Birmingham, Mr Yeo said protesters on the margins of anti-hunting groups had adopted tactics previously used against vivisectionists by animal rights extremists.
"There has been at least one case where there has been a visit to a house, and one or two instances where kennels have been damaged," he said.
"The inferred aim was to intimidate.
"I don't want to paint an Armageddon scenario but it would be foolish of the police service to assume it will never happen.
Hunting with dogs became illegal in England and Wales in February
"I don't think the future will be completely smooth for us."
Mr Yeo said there had been only five investigations into possible illegal hunts since the ban in England and Wales started - out of about 500 hunt meetings to have taken place in that time.
He said: "They may not all result in Hunting Act charges, but some of them may.
"A lot of this is where evidence has been gathered by pressure groups who may have been monitoring on the ground."
Mr Yeo told the conference anti-hunt groups felt police were not making enforcement of the ban a high enough priority but that countryside groups felt the ban was symbolic of a wider attack on traditional rural life.
The League Against Cruel Sports said it had contributed useful evidence to help the police investigations.
Spokeswoman Wanda Wyporska said dead foxes had been strung up and mutilated across the countryside and league members had received death threats.
"We strongly condemn any illegal action on either extreme of the hunting debate," she said. "Tempers in the countryside do need to be calmed."