Portable toilets were removed overnight from Chistye Prudy, an upmarket area in central Moscow where Kremlin critics have been converging to protest the reelection of Vladimir Putin.
Putin's spokesman, Dmitry Peskov, has called the sit-in illegal and said it would be dispersed.
Organizers say they were told the toilet cubicles "looked unaesthetic."
"I think authorities decided to waste us in the outhouse," socialite and opposition figure Ksenia Sobchak wrote on Twitter in a tongue-in-cheek reference to Putin's infamous pledge to flush Chechen rebels from Russia.
Sobchak said the owner of the toilets admitted he had been pressured by authorities. "I never thought I would get sucked into politics in the toilet business," she quoted him as saying.
In another humorous message, another Twitter user suggested that Moscow authorities planned to send new cubicles packed with riot police, Trojan-horse style.
Thankfully for protesters, the "toilet war" was brief. An hour later, organizers were able to have new cubicles delivered by a different company.
"We've agreed with the toilets, now we need to agree with Putin..." quipped Sobchak.
"Now the most important thing is literally not to crap out on [more literally, "f*ck up"] the protests :)"
-- Claire Bigg