When the Trump administration announced a series of high-profile immigration raids across Northern California in late February, officials framed the operation as necessary to protect the safety and security of the area from dangerous criminals. The operation briefly dominated headlines after the mayor of Oakland publicly warned her constituents of the impending raids.

But new data obtained by VICE News through a freedom of information request shows that the ICE raids, known as Operation Keep Safe II, netted few undocumented immigrants with recent, high-level criminal convictions. Instead, agents arrested and detained hundreds of people with minor or old criminal records — or with no criminal record at all.

Of the 233 people arrested between February 25 and 28, nearly half, or 111 people, had no criminal convictions. Out of those who did have convictions, the largest category of offense, amounting to 29 arrests, was traffic violations. The next largest, with 19 arrests, was drug violations, which can include crimes from trafficking to simple possession.

In total, 47 people, or 20 percent of the total number of arrests, had criminal convictions that ICE categorized as “Level 1,” which refers to “major drug offenses, national security crimes, and violent crimes such as murder, manslaughter, rape, robbery and kidnapping.”

But roughly half of those convictions date to more than 10 years ago. In total, 22 people — less than 10 percent of the immigrants arrested in the raid — had been convicted of a serious crime in the last decade.

“There’s a gap here between the rhetoric — the way this operation was described and the net results in terms of how many individuals were apprehended who posed an active, public safety threat to the U.S.,” said John Sandweg, a former official at the Department of Homeland Security and acting director of ICE under Barack Obama.

Raids of this scale, which target every individual in a given area subject to deportation, have become common under the Trump administration. But Operation Keep Safe II was one of the first in which the agency explicitly referenced the sanctuary policies of the targeted area to justify its tactics.

“ICE has no choice but to continue to conduct at-large arrests in local neighborhoods and at worksites,” the agency said in a press release at the time. “Ultimately, efforts by local politicians have shielded removable criminal aliens from immigration enforcement and created another magnet for more illegal immigration, all at the expense of the safety and security of the very people it purports to protect.” ICE did not respond to further requests for comment.

After Oakland Mayor Libby Schaaf publicly warned her city that ICE was about to launch the series of raids, the Trump administration turned her into a central villain in its fight against sanctuary cities.

“Here’s my message to Mayor Schaaf: How dare you?” Jeff Sessions said at a speech to a law enforcement association in Sacramento at the time. “How dare you needlessly endanger the lives of law enforcement officers to promote your radical open-borders agenda?”

The White House and congressional Republicans soon turned the operation into a high-profile illustration of the need to protect the public from the lawlessness of sanctuary cities. Acting ICE Director Thomas Homan said more than 800 “public safety threats” had eluded arrest as a result of Schaaf’s warning. (James Schwab, an ICE spokesperson in San Francisco, refused to repeat this claim, which he called misleading, and quit his job in protest; ICE subsequently retracted the claim.)

Months later, in May, Iowa Rep. Steve King introduced the “Mayor Libby Schaaf Act of 2018,” which would make it a crime punishable by up to five years in prison to “tip off illegal aliens about federal immigration enforcement efforts.” (The legislation did not advance.)

Since Trump took office, ICE has openly acknowledged that it considers any and all undocumented immigrants subject to arrest and deportation, regardless of their criminal background or other factors. But the Trump administration's argument against sanctuary cities isn't that every single undocumented immigrant, including law-abiding and longtime residents, should be arrested — it's that sanctuaries cities protect even those with criminal records. That’s why Trump has called them “the best friend of gangs and cartels.”

As the data behind Operation Keep Safe II shows, that argument is more rhetorical than real. Moreover, the Trump administration’s decision to broaden the range of immigrants it considers priorities for arrest has led to a dramatic rise in the number of apprehensions, but not a commensurate rise in actual deportations. More arrests simply tax an already overburdened system of immigration courts and detention centers.

“Their approach is to arrest every single individual,” said Sandweg, the former ICE director. “But the reality is when you arrest that many individuals, all you’re doing is further clogging the system.”

Correction 10/11 11:51 a.m. ET: A previous version of this story referenced an incorrect number of undocumented immigrants with "Level 1" criminal convictions from the last decade who were arrested in the raid. The text has been updated to reflect the correct number.