CHICAGO (CBS) — Some Chicago communities are on alert after news the Trump administration is sending border patrol agents to so-called sanctuary cities like Chicago to arrest undocumented immigrants.

Chicago is one of many cities across the country that bills itself as welcoming to immigrants and refugees.

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The president says it’s a sanctuary for illegal aliens.

Saturday the alderman of the 25th Ward and a group of volunteers were out walking the streets of Pilsen to let residents know that despite the president’s plan to deploy tactical enforcement units from the southern border here in the Windy City, they don’t have to live in fear.

Undocumented residents are told that they don’t have to open their doors unless the person knocking has a warrant.

City police and city workers have been instructed not to cooperate with immigration and customs enforcement workers and border patrol agents if they’re trying to track down undocumented residents.

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“We want to make sure that people feel protected, they know their rights,” said Ald. Byron Sigcho-Lopez. “So we’re going door to door to make sure that they know that our city is a welcoming sanctuary city, and we continue to protect them.”

Mary Lori Lightfoot also spoke on the situation.

“If anyone thinks that they can come here to our city and terrorize our residents into the shadows, let me say this: They’ve got another thing coming.”

The tactical enforcement team from the border region are expected to be sent to at least nine cities across the country ranging from New York on the East Coast to San Francisco on the west.

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The administration says this deployment is a direct response to policies adopted by sanctuary cities, which they say make it difficult for immigration agents to do their jobs.