Federal agents have shifted attention away from serious gun crimes and shady weapons dealers to focus on President Donald Trump’s crackdown on undocumented immigrants and deployments to patrol cities, according to current and former officials and data reviewed by CNN.

As part of a surge of 23,000 federal officers from a slew of agencies sent to work on Trump’s deportation efforts, the Bureau of Alcohol, Tobacco, Firearms and Explosives has reassigned 80% of special agents to immigration cases, according to a former senior official at the agency. Other agents have been assigned to surges Trump has ordered to Washington, DC, Los Angeles and other cities.

ATF is just one of several federal law enforcement agencies that have felt a notable impact on normal duties while assisting with the immigration mission, a CNN review has found.

ATF has lost one in every seven firearms license investigators to job reductions and retirements this year – and stands to lose 550 of the remaining 600 under Trump’s new proposed budget. The agency also has adopted onerous new rules that make it nearly impossible to revoke licenses from firearms dealers who fail to do mandated background checks or who break other laws, according to former and current ATF officials.

As a result, ATF did not move to revoke a single dealer’s license in the first four and a half months of this year, a former senior official said, adding that the bureau was on pace for at least a 90% drop from last year under President Joe Biden – when 195 dealers lost the ability to sell guns.

One ATF investigator said the shift in priorities is certain to have deadly consequences.

“They’re de-regulating an industry that sells tools that can take people’s lives in seconds,” said the agent who spoke on the condition of anonymity out of fear of reprisal. “We’ll have guns getting into the hands of people who definitely shouldn’t have them.”

Metropolitan Police and federal agents patrol near Union Station on August 30, in Washington, DC.