In a broadside on sanctuary cities that harbor criminal illegal immigrants, the acting head of Immigration and Customs Enforcement called them "un-American" and cited the worst: Chicago, New York City, San Francisco, and Philadelphia.

"Sanctuary cities, in my opinion, are un-American," said Thomas D. Homan in an interview with Secrets.

By harboring criminal illegal immigrants, the jurisdictions are boosting crime, he said.

"In the last year, I've read all these stories of how the crime rate has exploded in Chicago, and the president's trying to help them. We're stepping up our game in Chicago. Is Chicago doing everything that it can to decrease the criminal activity up there? I say no," Homan said.

"I say no because if you're an illegal alien, and you get arrested in the United States for a crime, and you get booked in Cook County, Chicago, my officers aren't allowed in the jail. They don't accept our detainers. They don't share information with us," he said.

Homan said that in denying to detain criminals, sanctuary cities end up putting them back on the street where they "will re-offend" and prompt ICE agents to take the dangerous step of tracking them down.

"Why would Cook County not want my officers, federal law enforcement officers, to go talk to somebody who is illegally in the United States that committed yet another crime against the citizens of this country? It's ludicrous," he said.

But, said the one-time Border Patrol agent, "They're a sanctuary city, they're proud of it."

He also singled out San Francisco and New York, both victimized by violent criminals.

"San Francisco. How soon they forget," he said in a reference to the July 1, 2015, slaying of 32-year-old Kathryn Steinle on city pier 14 by an illegal immigrant.

"Let's talk about New York City, the site of the most horrific terrorist event in this nation's history, and they don't accept our detainers," he said.

"New York City, they're proud of being a sanctuary city," Homan said.

"These jurisdictions, these cities, are choosing to shield people who violated the laws of this country that committed a crime against this country; they're going to shield them. So, what's next? Sanctuary cities for people who don't want to pay their taxes?" he asked.

Homan targeted his words at politicians, noting that police and sheriffs in many sanctuaries want to help ICE.

"The street cops that I talk to want to help. It's the politicians who want to make this a political game. It's not a political game. This is a matter of public safety and life and death we shouldn't be playing politics with this," he said.

Paul Bedard, the Washington Examiner's "Washington Secrets" columnist, can be contacted at pbedard@washingtonexaminer.com