Animal rights activists have claimed responsibility for an arson attack on an Oxford University sports pavilion.
Fifteen firefighters were called to The Queens College pavilion, off Abingdon Road, at 9.45pm last Saturday.
They spent an hour tackling a blaze in the roof, and managed to prevent it spreading to the rest of the building.
An animal rights cell has now claimed it carried out the attack in protest against the construction of the new £18m animal testing laboratory in South Parks Road, and has threatened that attacks on university properties will "escalate".
An anonymous posting on the Animal Liberation Front's Bite Back website said: "ALF volunteers gained access to the roof of the building and, after removing a section of roof tiling, placed an incendiary device containing 12 litres of fuel inside.
"Attacks will escalate in the face of an institution and government which have sought to destroy legal protest and continue to sanction violence to animals."
A spokesman for Oxford University said: "We are appalled by the contents of a statement concerning an arson attack on an Oxford college sports pavilion on Saturday.
"The university remains firmly committed to the completion of its new biomedical research facility."
A Thames Valley Police spokesman added: "Our investigation into the fire continues, with an increased focus on animal rights extremists."
A documentary looking at the issues surrounding the animal research laboratory is being shown on BBC2 at 9pm on Monday.