The mayor of Rome Gianni Alemanno has denied claims by Nichi Vendola, the leader of the left-wing Sinistra Ecologia Libertà (SEL) party, that Rome is a homophobic city.

Vendola, a high-profile gay politician, whose party is important to the outcome of the general elections in February, claimed that "In Rome I am afraid to go out by myself at night for fear of being insulted" over his sexual orientation. Alemanno responded by saying that Rome guarantees "acceptance and respect for all" and highlighted the city’s involvement with Gaypride.

Vendola’s remarks followed an anti-gay slur from Romano Amatiello, who is linked to the far right Casapound organisation and seeks election to the city council with the "Fascists of the Third Millennium". It was the latest in a series of anti-gay comments that Vendola has faced from Italian politicians in the recent past.

The clash between Alemanno and Vendola comes immediately after the controversy over homophobic graffiti which appeared outside the Cornelio Tacito high school in the Prati district of Rome over the weekend of 2-3 February. Prati is known for its far-right organisations such as Casapound.

The derogatory message is believed to have been directed at a 15-year-old, identified only as "P", a popular student who was elected to the school council and who happens to be gay. The message, which advised the student to quit the school, was accompanied by a Celtic cross, a symbol synonymous with contemporary Italian fascism.

The school quickly removed the graffiti, which it said was not the work of any of its students, and authorities are currently studying CCTV footage in an attempt to identify those involved. The institute's principal Giuliana Mori described the school's atmosphere as "relaxed and open" and said bullying was not an issue. For his part, the student responded ironically with "They have dedicated a mural to me, I'm almost glad!" before adding on a serious note “They cannot even hurt me. [Personally]I would give it little importance but there are those who pay with life itself, I cannot turn a blind eye."

Offering the student the "solidarity of all the city of Rome", Alemanno described the graffiti as the work of "cowards who believe in intimidating all those who combat violence and marginalisation".