CHICAGO, July 23 — Chicago Mayor Lori Lightfoot yesterday called on witnesses to come forward with information about an overnight shooting at a funeral and of a toddler, as the federal government stepped in to help the city curb a surge in violent crime.

Hours after Lightfoot pleaded for an end to Chicago’s "carnage” of gang violence, US President Donald Trump announced that hundreds of officers from the FBI and other federal agencies would reinforce the prosecution of criminals in the city.

Trump’s announcement followed an alarming night of violence in Chicago which included a drive-by shooting by suspected gang members at a funeral that wounded 15 people and the shooting of a three-year-old girl, who is expected to survive.

Trump has sought to promote a law-and-order message ahead of the November 3 presidential election, targeting cities controlled by Democrats. Critics say the administration is seeking to divert attention away from its widely criticised response to the coronavirus pandemic, one of the reasons he is trailing Democratic challenger Joe Biden in opinion polls.

At a news conference, Trump criticised Chicago politicians for what he characterised as "deadly” soft-on-crime policies and cited the recent spate of violence, including over the July 4 weekend, when 87 people were wounded by gunfire in the city and 17 were killed.

"For those people in Chicago and other cities where we’ll be: Help is on its way,” Trump said.

Trump had a brief call with Lightfoot yesterday evening to discuss the deployment, the mayor’s office said in a statement, adding that all new federal resources would be "investigatory in nature” and coordinated through the office of John Lausch, the US Attorney for the Northern District of Illinois and someone Lightfoot has said she trusts.

"The mayor has made clear that if there is any deviation from what has been announced, we will pursue all available legal options to protect Chicagoans,” the office said.

Trump had threatened earlier this week to send federal agents to Chicago, New York and other cities, sparking concern that the deployments would be similar to actions taken in Portland, Oregon, where federal agents without identifying badges have been accused of pulling protesters into unmarked vans, a possible violation of their civil rights.

US Attorney General William Barr told the briefing that the reinforcements to Chicago were part of a program called "Operation Legend.” The program was started this month to provide federal aid to officials in Kansas City, Missouri, in combating traditional violent crime, and does not involve the paramilitary-type forces deployed to Portland.

The effort in Chicago will include 100 investigators from the FBI, the Drug Enforcement Administration and the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), more than 100 members of the US Marshals Service Great Lakes Task Force and some 100 agents from a unit of the Department of Homeland Security already stationed in Chicago, the Justice Department said.

On Tuesday, Lightfoot had threatened to sue Trump if he sent unidentified federal agents to her city.

"The Trump administration is not going to foolishly deploy unnamed agents to the streets of Chicago,” she said.

Chicago has seen an explosion in violence this summer. There were 116 murders over the 28 days through July 19, an increase of nearly 200 per cent, police department data shows.

At a briefing earlier yesterday, Lightfoot pleaded with her constituents to help "end this carnage,” noting that the funeral at which the drive-by shooting took place had been for a victim of gang violence.

Police superintendent David Brown blamed turf battles among the roughly 117,000 gang members in the city of 2.7 million people, where one shooting begets another in an endless cycle of revenge.

"This same cycle repeats itself over and over and over again. This cycle is fuelled by street gangs, guns and drugs,” he said at the briefing. "Too many people in Chicago have been touched by gun violence.” — Reuters