CNN was first to report
earlier this year the formation of the team, which the ATF called in internal documents the "Chicago Crime Gun Strike Force."
The team includes an additional 20 ATF agents, who arrived June 1, according to a city official, as well as 12 Chicago police officers, two Illinois state troopers, six intelligence analysts and state and federal prosecutors.
"This new strike force will significantly help our police officers stem the flow of illegal guns and create a culture of accountability for the small subset of individuals and gangs who disproportionally drive violence in our city," said Chicago Police Department Superintendent Eddie Johnson.
President Donald Trump took to Twitter Friday to tout federal involvement.
"Crime and killings in Chicago have reached such epidemic proportions that I am sending in Federal help. 1714 shootings in Chicago this year," he tweeted.
Asked if Trump was right to take credit for this initiative, Kevin Navarro, first deputy superintendent of the Chicago police, responded, "These discussions with the superintendent [of Chicago police] have gone back to actually November. So, we have had two administrations that the superintendent has been dealing with in terms of getting extra assistance from ATF."
The department's chief of organized crime, Anthony Riccio, also pushed back against Trump.
"I'll say this about the violence in Chicago," he said. "Right now we are down 14% on shootings versus last year. That's well over 200 fewer people with gunshot wounds then we had at the same time last year. It's not success -- no one is celebrating that -- but it is a step in the right direction."
The President threatened to send in help early in his administration after months of campaigning against crime in Chicago and other major cities.
"If Chicago doesn't fix the horrible 'carnage' going on ... I will send in the Feds," he tweeted
four days after his inauguration.
The Trump administration has been criticized for calling Chicago a "war zone" and "totally out of control" despite not laying out a long-term vision for America's cities.
"Six months ago, we made it clear that we would welcome additional federal support, and six months later we appreciate the 20 new ATF agents that are now arriving," said spokesman Adam Collins. "But the progress CPD has made this year has happened without any of the new resources from the federal government we requested."
CNN also reported in April that a small team of eight FBI employees, including agents and analysts, from across the country were sent to Chicago on a temporary assignment.
A law enforcement official told CNN Friday that the eight FBI employees have left the city. They spent a few weeks in Chicago to help combat violent crime and then returned to their regular field offices before the end of May. The official added that there are no current plans to send any additional FBI resources to Chicago.
Meanwhile, Chicago police say crime in the city has decreased from 2016, when there were 4,331 shooting victims and 762 homicides. Chicago police said Friday there has been a 14% drop in violent crime overall in the city compared to last year -- with the two most violent districts seeing a 33% drop in violent crime -- and there have been 234 less people shot this year.
The homicide rate, however, has remained flat.