A Los Angeles synagogue was vandalized on Wednesday morning with pro-Palestinian graffiti.

A Twitter post stated that the Baba Sale Congregation was vandalized a short time after 5 a.m., at a point when morning prayers were underway.

Anti-semitic Vandalism @ Baba Sale Congregation this morning around 5:20 AM. It seems that the perpatratiors waited for congregants to enter and then sprayed the grafitti, so that when they come out they should see it… — Rabbi Yonah (@RabbiYonah) September 11, 2019

The graffiti, scrawled in red spray paint, read, “Free Palestine.” It has since been painted over.

The vandalism came on the 18th anniversary of the 9/11 terrorist attacks.

Police are reportedly investigating the incident.