Columbia University was a victim of infrastructural sabotage on Wednesday when an extremist anti-Zionist group flooded the toilets of an academic building with concrete to mark the anniversary of an alleged killing of a Palestinian child.

“Restroom facilities at the School of International and Public Affairs were vandalized with graffiti that included disturbing, personal attacks,” the university said in a statement issued after the attack.

“Acts of vandalism of university buildings and property and attempts to harass and intimidate members of our community are unacceptable and abhorrent and will not be tolerated at Columbia.”