Animal rights activists claim they have conducted a series of attacks against firms working for Oxford University as they continue their campaign against its new animal laboratory.
The Animal Liberation Front claims to have glued and disabled card swipe devices on doors at university buildings last month and vandalised vans and premises belonging to four local firms.
Bite Back magazine's website, which focuses on animal rights issues, received two anonymous reports claiming responsibility for the attacks, in protest against the construction of the �18m animal testing facility in South Parks Road.
The first said: "Throughout the month of June, the ALF were busy taking on Oxford University.
"A number of the card swipes present on most buildings as security devices were glued or disabled. It was nice to see that some of them have now had to be removed together."
The second posting said: "On Thursday, July 18, the ALF struck at four sites in Oxford.
"There were premises or vehicles belonging to building contractors, which do regular work for the university."
According to the ALF, locks were glued and gates D-locked at Monard Electrical contractors, in Denmark Street; a Dark & Taylor van was spray-painted, in Dene Road, Cowley; a Lowe & Oliver van was spray-painted at an undisclosed location; and a DHL parcels van was "paint-strippered" in Catherine Street, East Oxford.
The companies either declined to comment, or managers were unavailable for comment.
Thames Valley Police spokesman Tim Prince said: "So far no-one has been arrested in connection with these offences."
Robin Webb, a spokesman for the ALF, said: "These activities will continue, while the lab is being constructed. The university can take out as many sweeping injunctions against activists as it likes, but it can't clamp down on those who are already acting outside the law."
The DHL vehicle was targeted for continuing to act as a courier for Huntingdon Life Sciences, according to the ALF's statement.
These are the latest in a series of attacks launched by the ALF against Oxford University, inclduing torching the Hertford College boathouse, off Donnington Bridge Road.
A spokesman for Oxford University said: "We are unable to comment in detail on the incidents as these are currently under investigation by police.
"It is totally unacceptable that such criminal activities designed to harass and intimidate should be carried out against the university and those associated with it."