Security officers welded shut the entrance to an art exhibition on police violence in Moscow to halt the opening, organizers and artists told Russian media Monday.

The exhibition, which bills itself as an attempt to document “the mass beatings of civilians in Moscow and St. Petersburg,” timed its opening to coincide with President Vladimir Putin’s 67th birthday.

“We had just finished mounting the exhibits, but then people started coming from the district council, then the Emergency Situations Ministry, and finally the police,” curator Vadim Sobolyov told news site The Village.

What was supposed to be the exhibit’s opening day was marked by a series of unannounced visits from officials, co-organizer Veronika Polonskaya told Mediazona. She said district council officials took photographs of the exhibits in the morning, they were followed by fire inspectors, then a consumer protection watchdog official before police arrived in the evening.

No one was detained during the police raid, but the artwork and documents remain inside the gallery behind the welded doors, according to Dozhd TV.

The gallery hosting the exhibition, Dordor, said it has suspended all of its events until further notice and that it does not know “what provoked the authorities’ actions.”

“We do art and we’re not interested in the hype surrounding the gallery,” it wrote on its Instagram page.

The “Osen Pakhana” (“Autumn of the Tough Guy”) exhibition’s disruption follows a string of similar incidents in which police and pro-Kremlin activists raided theater productions and a seminar on how to behave with law-enforcement officers during protests.

The largest sustained protest movement in years gripped Moscow over the summer, sparked by the authorities’ rejection of opposition candidates in a local vote. Police detained thousands of demonstrators, at times violently, during unauthorized rallies.

A handful of people have been jailed in connection with the protests, catalyzing nationwide online and in-person campaigns in their support.