Former President Joe Biden was briefly heckled while delivering the keynote address at a Maryland Democratic Party gala Saturday night, during which he attacked President Donald Trump and defended his record in office.

Barely a few minutes into his speech, as he discussed how the story of America features a “constant push and pull between peril and possibility,” attendees began jeering loudly at Biden, who continued speaking as the interruption eventually subsided. It is unclear what the disruptors said or why they shouted.