Los Angeles’ Democratic mayor, Eric Garcetti, was shouted down by socialist protesters during a speech Monday at the University of Southern California.

Mr. Garcetti was less than a minute into his keynote speech at a campus event celebrating the 70th anniversary of the Universal Declaration of Human Rights when he was interrupted by protesters organized by the Los Angeles Community Action Network and the Los Angeles chapter of the Democratic Socialists of America, among others, The Los Angeles Times reported.

The protesters specifically took issue with gentrification and the Los Angeles Police Department’s clean up of homeless encampments. They stood up one by one and shouted their grievances, of which Mr. Garcetti made an effort to address, The Times reported.

As he spoke, protesters reportedly sang the tune of “Santa Claus Is Coming to Town,” with the altered lyrics: “You better watch out, you better not cry, Eric Garcetti is telling us lies, human rights violations happening now.”

Some attendees applauded in support of the mayor but the protests continued. After about 20 minutes of back and forth, Mr. Garcetti left the stage without delivering his speech.

The mayor’s spokesman Alex Comisar called it “unfortunate” that a “very small group of people denied the audience an opportunity to hear [Mr. Garcetti‘s] remarks — but he respects the 1st Amendment rights of all people who want to make their voices heard on issues that they care deeply about.”

Mr. Garcetti, who has served as mayor since 2013, is being floated as a potential 2020 presidential candidate.