Vandals burn 'STFC' into Oxford's Kassam Stadium pitch
Vandals broke into Oxford United's Kassam Stadium and burnt 'STFC' - the initials of local rivals Swindon Town FC - into the pitch.
The men were captured on CCTV on Friday night, police said.
A spokesman for the Swindon club said it "deplored" the actions of those involved and would fully support the police in their investigations.
Thames Valley Police are studying CCTV footage and working with the club to catch those responsible.
BBC Radio Oxford's Nathan Cooper said: "It looks like they have almost set fire to the pitch and made the lettering in the penalty area."
The incident comes in the build up to Oxford's match at Swindon on Sunday - the first derby meeting of the two clubs since 2002.
Anyone with information is asked to contact Thames Valley Police.