A top official with Immigration Customs and Enforcement (ICE) announced Wednesday that 800 illegal aliens in Northern California avoided arrest because of an Oakland mayor’s warning about ICE raids in the area.

Oakland Mayor Libby Schaaf warned San Francisco Bay Area residents Saturday of potential ICE raids that would take place over the weekend, causing tensions between federal immigration officials and California state officials.

“What she did is no better than a gang lookout yelling ‘police’ when a police cruiser comes in the neighborhood, except she did it to a whole community,” Thomas Homan, acting director of ICE, told Fox & Friends.

Homan said the Justice Department is investigating whether Schaaf obstructed justice. He added that her actions may have allowed criminal illegal aliens to stay in Oakland, making residents feel less safe.

Even after Schaaf’s warning, ICE announced Tuesday that the agency arrested 150 illegal aliens during an operation called “Keep Safe.”

Half of those taken into custody by ICE agents for being in the country illegally had been convicted of crimes.

Schaaf, a Democrat, said that she does not “regret” divulging information about the raids, even if she is under federal investigation.

“I do not regret sharing this information,” Schaaf said. “It is Oakland’s legal right to be a sanctuary city and we have not broken any laws. We believe our community is safer when families stay together.”