CHICAGO (AP) — President Donald Trump opened a speech to a conference of police chiefs on Monday by slamming the host city as "embarrassing to us as a nation" under the leadership of the city's top cop, who skipped the event over disagreements with Trump's immigration policies.

Trump has frequently slammed Chicago for its crime problems and status as a sanctuary city, one of scores of cities around the country that refuse to work with federal authorities to round up people who are living in the U.S. illegally.

"It's embarrassing to us as a nation," Trump said. "All over the world they're talking about Chicago. Afghanistan is a safe place by comparison."

Trump also criticized Police Superintendent Eddie Johnson, who angered Chicago's police by skipping Trump's first appearance in the city as president.

"More than anyone else he should be here, because maybe he could maybe learn something," Trump said, claiming Johnson puts the needs of illegal immigrants above the needs of the law-abiding residents of Chicago.

"Those are his values and frankly those values to me are a disgrace," Trump said, vowing to never to give priority to the needs of illegal immigrants. "I want Eddie Johnson to change his values and to change them fast."

Johnson's decision to skip Trump's address angered the city's chapter of the Fraternal Order of Police, which said in a Facebook post that "such a gesture would be an insult to both President Trump and the office of the presidency itself and would be a mark of disgrace upon the city throughout the entire nation, including Mayor Lori Lightfoot." Lightfoot has also refused to meet with Trump while he is in her city.

Then FOP Lodge 7, which represents rank-and-file Chicago police officers, announced that it had cast a vote of no confidence in Johnson.

The vote might please Trump, who likes to tell officers not to treat crime suspects so gently and was cheered at last year's gathering of the same police chiefs' organization in Orlando, Florida, when he advocated the use of the "stop and frisk" policing tactic that has been deemed unconstitutional.

The president's visit also comes as more than 25,000 members of the Chicago Teachers Union have been on strike since Oct. 17.

Johnson is also under an internal investigation opened after he was found earlier this month sleeping in a city-owned vehicle.

Lightfoot said the superintendent, who called for the investigation, told her he had "a couple of drinks with dinner" before he fell asleep at a stop sign while driving home. Johnson said the episode was related to a change in his blood pressure medication.

While in Chicago, Trump is scheduled to headline a campaign luncheon that's set to raise approximately $4 million for a joint fundraising committee benefiting Trump's reelection effort and the Republican National Committee, according to the GOP.