Vandals superglued shut every public toilet in Hove.
An investigation has been launched after all 24 were affected.
It is estimated it will cost Brighton and Hove City Council almost £1,500 to repair the damage.
The alarm was raised on Saturday morning by staff working for the council's cleaning contractors.
They told police they had been unable to open any of the 32 doors to public toilets in Hove because the locks had been superglued.
Inspector Mark Powles said: "In addition, a screw had also been drilled into the lock barrel and the head filed off to prevent it from being removed.
"It was a pretty determined effort by someone to stop the toilets from being opened.
"At the moment we have nothing to suggest a link with Gay Pride but we are keeping an open mind pending the outcome of the investigation."
A council spokeswoman said: "If this was a homophobic attack aimed at the gay population of Brighton and Hove, we would be absolutely horrified.
"It has happened several times over the past three years but never on this scale. In the past it has only been a few at a time.
"If there was a link with Gay Pride we would take it very seriously and would be very concerned that there could be a hate attack at this level.
"Our staff worked very hard late into the night on Saturday to put the damage right and to get the toilets open again the following day."
Gay writer and broadcaster Simon Fanshawe said he would be "saddened" if it proved to be linked to the Pride celebrations.
He said: "It is an absolutely bizarre way for someone to express their anger against the gay population.
"Pride brought more than 50,000 people into the city for the celebrations at the weekend and that can only be of benefit to everyone."
Detective Inspector Fiona Grant, of the city's anti-victimisation unit, said: "At the moment there is no evidence or information which leads us to believe this was a homophobic attack.
"We would be reluctant to treat it as such until we have such evidence."
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