Rep. Jamie Raskin was forced to cancel an event with mental health experts on Donald Trump’s mental fitness to be president after the congressman’s office received a string of threats.

The event was scheduled for Thursday at a senior center in Maryland and intended to cover issues such as Trump’s perceived tendency to inspire violence.

But Raskin, a Maryland Democrat, called it off just 24 hours before its start time due to “significant safety risks” to attendees, Bandy X. Lee, a Yale professor who was scheduled to speak at the event, told the Daily Beast.

“Sorry about tomorrow night — we’ve been getting so many threats,” Raskin said, according to Lee, a psychiatrist who has led the charge among mental health professionals publicly decrying the president’s mental fitness for office.

Raskin has been one of the Democratic House caucus’ most vocal critics of the White House over the past year. Trump supporters were furious when he submitted a bill last April to form an 11-member panel of physicians and psychiatrists to examine the president’s physical and mental fitness to serve.

“Whenever my boss talks about the 25th Amendment there will be an uptick in comments on social media, or phone calls, or emails, that contain either explicit threats or generally violent and hateful language,” Lauren Doney, Raskin’s communications director, told The Daily Beast.

Lee is the editor of “The Dangerous Case of Donald Trump,” an essay collection that argues Trump has an affinity for violence that endangers the public. She has become a political target for right-wing news curators such as Mike Cernovich, “Pizzagate” conspiracist Jack Posobiec and Breitbart News.

Proclamations against the president by her and others in her field have also been scrutinized by the American Psychiatric Association for tiptoeing around the “Goldwater rule,” the ethical standard for psychiatrists that bars them from issuing diagnoses of public figures without a face-to-face examination or a subject’s consent.

Last March, the APA broadened the Goldwater rule’s language to forbid its members from even offering statements about a public figure’s fitness and behavior.