A roomful of police union officials laughed uneasily Tuesday when President Donald Trump asked them to identify officers who hadn't backed him in the election.

The Trump administration invited the head of Chicago's Fraternal Order of Police to meet with him in Washington, D.C., to discuss the city's gun violence -- which the president has described as "carnage" requiring possible federal intervention.

"I made a crucial pledge: We will always support the incredible men and women of law enforcement. I will always have your back 100 percent," Trump told the gathering.

"Sadly, our police are often prevented from doing their jobs," he added. "In too many of our communities, violent crime is on the rise. These are painful realities that many in Washington don't want to talk about. We have seen it all over."

Trump thanked the police union and its president, Dean Angelo, for their support during his election campaign and bragged about the backing he'd gotten from police officers.

"I guess you probably know the numbers were extremely lopsided, right?" Trump said, looking around the room. "I'm just trying to figure out the few people who voted the other way. Who are they? Who are they? Find out who they are, please, and let us know."

Some of the police officials laughed, as the president returned to his prepared remarks.