A 75-year-old woman suffered cuts to her arms as tempers flared at a demonstration against the Star Wars project.
The incident happened as members of the Campaign for Nuclear Disarmament held a rally outside the United States communications base at RAF Croughton, near Bicester.
Jean Kaye, of Annesley Road, Rose Hill, Oxford, was trying to retrieve the CND's American flag after three American women had grabbed it.
The demonstration
Her arms were caught on the lock of the metal gates.
She was taken by ambulance to The Horton Hospital, Banbury.
Mrs Kaye was among 30 Oxford demonstrators.
She said: "I'm a bit shaken up. I can't believe they could get so angry."
Base spokesman, Sgt Art Webb, said: "We do not condone any behaviour of this sort.
"Croughton respects the property of others."
Most of the demonstration passed off peacefully. A clown entertained the crowd.
**Picture: Ed Nix
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