Antisemitic markings were found on the Piedmont High School campus earlier this week, according to a police statement issued Wednesday.

A swastika and the word “Hitler” were found in chalk behind the school gym, the school district said. Pictures have not been released.

The Piedmont Police Department said it was working with the school district to “investigate the circumstances” surrounding the markings. The department also said it would be increasing police presence at the school “out of an abundance of caution,” and in light of Tuesday’s mass shooting at Robb Elementary School in Uvalde, Texas.

“The safety and security of students and staff are our highest priority,” the police statement said.

Piedmont High, a relatively small public school in the affluent town, surrounded by Oakland, has a student body of about 850. It was recently ranked fifth in academic performance among San Francisco Bay Area high schools.

The Piedmont Unified School District informed parents of the incident in an email Wednesday, denouncing antisemitism and “messages of hate.” Superintendent Randall Booker asked parents to discuss the issues around bigotry with their children.

“Eliminating anti-Semitism and its long history of hate and persecution is a collective effort,” Booker wrote.

The incident follows a proclamation issued May 16 by the Piedmont City Council and Mayor Teddy Gray King recognizing Jewish American Heritage Month. “Piedmonters share an obligation to condemn and combat antisemitism,” the proclamation reads.

Placing a Nazi swastika on private property or in certain public places, including schools, is a hate crime punishable by jail time and fines under California’s terrorizing threats statutes.