Story highlights ICE carries out operation that arrested more than 150 people

It criticizes Oakland mayor for announcing that operation was going to happen

San Francisco (CNN) Oakland Mayor Libby Schaaf said she has no regrets for warning the public of impending immigration operations and that she would do it again.

Schaaf has come under heavy criticism from the US Immigration and Customs Enforcement for announcing that immigration operations were going to happen the day before they started.

More than 150 people alleged to have violated immigration laws were arrested in Northern California as part of ICE operations that began Sunday, the agency announced Tuesday. Half of those arrested had criminal convictions, according to ICE.

In the same statement announcing the arrests, ICE Deputy Director Thomas D. Homan slammed Schaaf's decision to alert the public as "reckless" and "irresponsible."

Schaaf had issued a warning on Saturday and held a press conference the following day, announcing that she had learned that ICE would conduct operations in the Bay Area.