U.S. President Donald Trump's son Eric Trump said the U.S. Secret Service took an employee of a Chicago cocktail lounge into custody after she allegedly spit on him.

It was "purely a disgusting act by somebody who clearly has emotional problems," Eric Trump told Breitbart News in a telephone interview.

He implied it was an example of Democrats' showing frustration for the successes of his father's Republican administration.

"For a party that preaches tolerance, this once again demonstrates they have very little civility," he said. "When somebody is sick enough to resort to spitting on someone, it just emphasizes a sickness and desperation and the fact that we're winning."

The incident is alleged to have occurred Tuesday night at The Aviary in Chicago's West Loop area. The Associated Press sent an email Wednesday seeking comment on behalf of the lounge.

Chicago police spokesperson Anthony Guglielmi said on Twitter that officers assisted the Secret Service with a "law enforcement matter" and deferred inquiries to the agency.

The Secret Service, White House and Trump Organization, which Eric Trump helps run, didn't immediately respond to requests for comment from the AP.

There have been other public confrontations involving those associated with Trump and his administration.

In June 2018, The Red Hen restaurant in Virginia refused to serve White House press secretary Sarah Huckabee Sanders at the request of gay employees who objected to how Sanders defended Trump's desire to bar transgender people from the military. That triggered debate about whether politics should play a role in how administration officials are treated in public.

Several other Trump administration officials, including Homeland Security Secretary Kirstjen Nielsen, were confronted in public around that time amid fury over an administration policy that led to an increase in the number of migrant children being separated from their parents after crossing the border illegally.