In February, shortly after Mr. Trump's inauguration, the A.T.F. announced that it would send more agents to Chicago.
"This is a man who said his first duty is the safety and security of all Americans".
The number of murders and shootings in the Midwestern city of 2.7 million has been down slightly so far this year from the same period last year, according to police.
In 2016, the number of murders in Chicago totaled over 760, a jump of almost 60 percent, and was more than NY and Los Angeles combined. "1714 shootings in Chicago this year", he tweeted.
In 2013, the then-businessman and TV personality labelled the Midwestern city a "shooting disaster" and called for a non-optional "stop and frisk" policing system to be implemented.
NYC subway train derails, scaring passengers and injuring 34
Emergency personnel have responded to a Manhattan subway station where passengers were reporting smoke and a loss of power. The Metropolitan Transportation Authority (MTA) confirmed in a Twitter post that an "A" train had derailed at 125 Street.
Sessions said the anti-crime policies in Chicago have not worked and police "have been demoralized in many ways".
According to the department's release, the "Chicago Crime Gun Strike Force" will include Chicago police officers, federal agents, IL state troopers, "intelligence analysts" and state and federal prosecutors. The group became operational on June 1, Sessions said. Roughly 40 ATF agents have already been working with local and state police on reducing gun violence in the city.
Meanwhile, Chicago police say crime in the city has decreased from 2016, when there were 4,331 shooting victims and 762 homicides.
Chicago Mayor Rahm Emanuel's office confirmed Friday that the ATF agents were in the city and praised the police department's progress in addressing the city's challenges with violence. A specially-equipped mobile van that can process bullets and shell casings will help the task force investigators build cases against shooters and gun dealers, ATF spokesman Dave Coulson told the Sun-Tmes.
"There are multiple roads that allow you to make sure you make the changes and reform", he said.
"The goal is the prosecute as many of these guys as possible federally where they will serve longer prison terms", Anthony Riccio, head of the Chicago Police Department's organized crime unit, told the newspaper.