Officials at Sussex University are trying to work out who is behind the antisemitic graffiti that has appeared on the campus.

A message scrawled on a blackboard in the university’s Library Square, read: “Jet fuel can’t melt Jews. Holocaust was an inside job.”

It was discovered last week by a shocked student who reported it to the University on Twitter.

In another incident a poster advertising a talk by Israeli academics Yoav Peled and Horit Herman Peled, based on their book The religionisation of Israeli society, was defaced with swastikas.

Annie Pickering, the student union president, said students had been left frightened by the incidents.

She told the university newspaper: “The swastikas have scared us as much as anyone else and we are working with students and the university to remove the signs and if possible work out who is behind this.”

In a statement Adam Tickell, the vice chancellor, said “immediate action” had been taken to remove the graffiti.

He said: “Whatever your race, religion, gender identity, sexuality or age, or if you have a disability – Sussex is your home and you will be protected from discrimination or abuse.

“We will not tolerate any acts which are illegal or incite hatred.”

A spokesperson for the university said: “As soon as we were made aware of the wording on the art installation, we took immediate action to have it removed. 

“We will not tolerate any form of hate speech in our community. Where there is evidence that an individual or a group is inciting violence, causing a breach of the peace, or is transgressing the bounds of lawful free speech or assembly, we will always take the appropriate action. 

“As a truly international institution, we encourage all members of our community and visitors to our campus to express opinions freely, within the law. However, we must balance this commitment to freedom of speech with our commitment to equality and diversity, which is central to the ethos of our community.”