The White House on Thursday said the Department of Justice was reviewing the actions of Oakland Mayor Libby Schaaf, who last weekend alerted residents in advance of an Immigration and Customs Enforcement raid in Northern California.

"I think it's outrageous that a mayor would circumvent federal authorities and certainly put them in danger by making a move such as that," White House Press Secretary Sarah Huckabee Sanders told reporters.

Schaaf has defended her statement, saying she felt it was her duty to warn residents of the ICE action, the Los Angeles Times reports.

Oakland, like many California cities, has declared itself a sanctuary for those here illegally, and officials there have vowed to fight President Trump's immigration crackdown.

"The Oakland mayor's decision to publicize her suspicions about ICE operations further increased that risk for my officers and alerted criminal aliens — making clear that this reckless decision was based on her political agenda with the very federal laws that ICE is sworn to uphold," ICE's acting director, Thomas D. Homan, said in a statement Tuesday.

Speaking on "Fox and Friends," Homan added that the mayor's warning helped an estimated 800 "criminal aliens" avoid capture. He also said federal authorities were examining her actions.