"I just couldn't bear the burden -- continuing on as a representative of the agency and charged with upholding integrity, knowing that information was false," he told CNN on Monday.
Schwab cited Acting Director Tom Homan and Attorney General Jeff Sessions as being the purveyors of misleading and inaccurate information, following Oakland Mayor Libby Schaaf's controversial decision to warn the community of an upcoming ICE raid.
ICE released a press release on February 27
about the operations in Northern California in which Homan stated that "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."
Sessions also repeated a similar estimate in his remarks while visiting Sacramento last week.
"Those are 800 wanted criminals that are now at large in that community -- 800 wanted criminals that ICE will now have to pursue with more difficulty in more dangerous situations, all because of one mayor's irresponsible action," Sessions had said.
Schwab said he took issue with their characterization.
"Director Homan and the Attorney General said there were 800 people at large and free to roam because of the actions of the Oakland mayor," he told CNN. "Personally I think her actions were misguided and not responsible. I think she could have had other options. But to blame her for 800 dangerous people out there is just false."
"It's a false statement because we never pick up 100% of our targets. And to say they're a type of dangerous criminal is also misleading."
Schwab said he brought up his concerns to ICE leadership and was told to "deflect to previous statements. Even though those previous statements did not clarify the wrong information."
"I've never been in this situation in 16 almost 17 years in government where someone asked me to deflect when we absolutely knew something was awry -- when the data was not correct" he said.
Schaaf applauded Schwab for speaking out. "I commend Mr. Schwab for speaking the truth while under intense pressure to lie," the Oakland mayor said. "Our democracy depends on public servants who act with integrity and hold transparency in the highest regard."
Schwab also said he is a registered Democrat, but has been a loyal federal servant, regardless of which party is in power.
Responding to Schwab's remarks on Tuesday, ICE stood by its criticism of Schaaf. "Even one criminal alien on the street can put public safety at risk and, as Director Homan stated, while we can't put a number on how many targets avoided arrest due to the mayor's warning, it clearly had an impact," ICE spokeswoman Liz Johnson said.
"While we disagree with Mr. Schwab on this issue, we appreciate his service and wish him well."
CNN has also reached out to the Department of Justice for comment.