Federal immigration agents have arrested more than 150 people in Northern California who they say have violated immigration laws for deportation, as tensions between the government’s push to more vigorously enforce the law and state officials have spilled into the fore.

About half of the people arrested also had criminal convictions, according to Immigration and Customs Enforcement, which is largely in charge of enacting President Trump’s push for more stringent enforcement of the country’s immigration provisions.

The arrests began Sunday, a day after Oakland Mayor Libby Schaaf, a Democrat, issued an unusual warning to her constituents that she had learned from “multiple credible sources” that ICE was planning an operation in the Bay Area.

Schaaf is one of many mayors around the country at the helm of a “sanctuary city” — one that has barred city employees from helping federal immigration agents — and she has been particularly outspoken on the issue of immigration, saying in interviews that she’d be willing to go to jail to protect residents from deportation.

On Tuesday, ICE Deputy Director Thomas D. Homan seemed to blame her for the fact that a number of suspected undocumented immigrants were still at large.

“Thanks to the dedicated and professional work of ICE deportation officers, we were able to remove many public safety threats from the streets of the Bay Area during the past few days,” he said in a statement. “However, 864 criminal aliens and public safety threats remain at large in the community, and I have to believe that some of them were able to elude us thanks to the mayor’s irresponsible decision.”

The Justice Department has also been putting pressure on sanctuary cities.

Earlier this month it sent letters to 23 jurisdictions demanding documentation that it said would show whether they were “unlawfully restricting information” from federal immigration authorities.

“Sanctuary jurisdictions like San Francisco and Oakland shield dangerous criminal aliens from federal law enforcement at the expense of public safety,” Homan said. “Unlike the politicians who attempt to undermine ICE’s critical mission, our officers will continue to fulfill their sworn duty to protect public safety.”

Many local officials argue that the threat of deportations instead weaken the efforts of local law enforcement officers, saying that immigrant communities are less likely to work with officials for fear of reprisal.

Another ICE official, Matthew Albence, attacked Schaaf on Tuesday.

“We have a politician that’s going to try to score cheap political points on the backs of the men and women of ICE, and that’s unconscionable,” he said on Fox News, according to the San Francisco Chronicle.

ICE said it had arrested 20,201 people suspected of being in the country illegally in California in 2017; 81 percent had some criminal conviction, it said.

During a meeting last week, Trump said he was thinking of pulling ICE officials from California because of frustration with the state, though it was not clear how serious his proposal was.

A so-called sanctuary state bill passed by California lawmakers last year formalizes restrictions on state and local law enforcement agencies from cooperating on federal immigration cases, unless the people in question have been convicted of violent crimes, sex- or arson-related offenses and some other felonies.

Cleve R. Wootson Jr. contributed reporting to this article. 

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