Chicago federal intervention: Tracking surge in immigration enforcement operations | Updates

Nearly 25% of FBI agents are now working on immigration enforcement, according to numbers provided by the FBI to Sen. Mark Warner's office. But those numbers get even higher when looking at some of the biggest field offices around the country: up to 45% of those FBI agents are working on President Donald Trump's immigration push.

As operation "Midway Blitz" continues in Chicago, and more federal agents are deployed around the country to Democratic cities, prompting large public outcry, the ABC7 I-Team has learned 23% of FBI agents nationwide have been tasked with immigration enforcement. Traditionally, the FBI investigates foreign spies, terrorism, cyberattacks and transnational gangs.

"My concern is that if you're moving agents away from those vital responsibilities to engage in civil immigration enforcement, you're going to see a decrease in the number of FBI investigations in those areas and an increase in the threat to the country," former Homeland Security Assistant Secretary for Counterterrorism John Cohen told the I-Team.

He says there is a finite number of law enforcement resources working on complex public safety investigations.

"If FBI agents aren't working on Joint Terrorism Task Forces, then there are fewer terrorism investigations. If FBI agents are not working on drug gang task forces, then there are fewer investigations into violent street gangs and drug trafficking cartels," Cohen said.

And with such a large contingent pulled from their duties, he says drug cartels and bad actors are watching. Click here for more.

A chase involving federal agents led to a crash Tuesday afternoon on Chicago's East Side, officials said. After the crash, a crowd gathered around agents on the scene.

Chopper 7 was over the scene about 12:10 p.m., and there was a large number of Chicago police squad cars and Border Patrol agents on the scene in the 10500-block of South Avenue N.

Federal agents were involved in a chase before an East Side, Chicago crash on South Avenue N, and a crowd was tear gassed in the area Tuesday.

A neighborhood resident said a red SUV was being chased by federal agents before a crash in the area.

The Department of Homeland Security said a vehicle, driven by someone living in the U.S. without legal permission, rammed a Border Patrol vehicle that was part of an immigration enforcement operation and tried to drive away.

Border Patrol followed the vehicle for about 30 minutes, and stopped it using a precision immobilization technique, or PIT, maneuver.

Two people, both living in the U.S. without legal permission, tried to run away, DHS said. They were taken into custody.

A white Expedition and the red SUV were damaged.

Surveillance video shows they had been chasing the red vehicle in circles around the neighborhood before the crash.

After the crash, there were a number of unmarked federal vehicles in the middle of an intersection.

Bystanders surrounded the dozens of agents in a tense standoff. Some were holding flags and others were holding phones, recording.

ABC7 Chicago crews on the ground saw some tear gas deployed, after something, possibly eggs, was thrown at agents.

Chicago police said they had responded to the crash just after 11:05 a.m.

CPD had tried to get between federal agents and the residents gathered to deescalate, police said, but then rocks were thrown at the federal agents.

A large amount of tear gas was deployed about 12:40 p.m.

Those gathered quickly dispersed.

Federal agents had masks, but CPD did not. Some officers appeared to be affected by the gas.

CPD said 13 officers were exposed.

Federal agents made several arrests, including at least one teen.

A WGN employee who was detained by federal agents last week is now telling her side of the story.

Debbie Brockman, speaking out through her lawyer, says she was heading to work when Border Patrol agents forced her onto the ground and cuffed her. She also says she was not working at the time.

DHS says Brockman was detained because she allegedly threw something at the agents.

Brockman disputes those claims, saying she was just walking to a bus stop in a North Side neighborhood.

She was later released without charges. Brockman's attorney says they are considering legal action.

In a statement, WGN says Brockman is not a member of their news staff and was not working at the time. Click here for more.

DHS released new information about the threats it says federal agents face while "protecting our borders and communities."

DHS says it has obtained what it calls "credible intelligence" that Mexican cartels have issued a tiered bounty program for hits against ICE and Border Patrol agents.

The release from DHS specifically mentions Pilsen and Little Village, where it alleges gang members affiliated with the Latin Kings have organized "spotter networks," deploying people equipped with firearms and radio communications on rooftops.

Click here for more.