US President Donald Trump announced he was deploying more federal agents to Chicago and other major cities Wednesday to help battle a jump in gun violence and shooting deaths.

The move came a day after 15 people in Chicago, the country's third largest city, were wounded in a drive-by shooting at a funeral for a man recently gunned down in what police called gang violence.

But officials made clear that the government was not sending paramilitary forces in to address protests, as it has in a deeply controversial move in Portland, Oregon.

"I'm announcing a surge of federal law enforcement into communities plagued by violent crime," Trump said at the White House, with Attorney General William Barr and the FBI and Department of Homeland Security chiefs in the audience. 

"We want to make law enforcement stronger, not weaker," he said, adding that, for the cities, "Help is on the way."

- Epidemic of gun violence -

Barr said officers from the FBI, US Marshals Service, Drug Enforcement Administration, and Bureau of Alcohol, Tobacco and Firearms, would be boosted in Chicago and Albuquerque, New Mexico, as part of ongoing Operation Legend, named after four-year-old LeGend Taliferro, shot and killed while he slept on June 29 in Kansas City.

Around 200 officers from those bodies have already been deployed in Kansas City to help with the gun violence there.

The operation is "to protect the residents of those cities from senseless acts of deadly violence by targeting those involved in gang activity and those who use guns to commit violent crime," said Barr. 

Some 200 more agents would be deployed to Chicago and another 30 to Albuquerque, Barr said.

Shootings have spiked in a number of US cities this summer. Chicago has suffered about 1,640 shootings and 414 murders this year, according to police data.

Both figures are up around 50 percent from a year ago. Officials blame frustration and economic pains from the COVID-19 crisis, stepped gang rivalries, and easy access to guns. 

New York shootings are also running at their highest levels in over a decade, and many other urban areas are facing similar challenges.

Shootings have accelerated during the summer across the country. More than 60 people were shot in Chicago, including 14 fatalities, over the past weekend alone.

- Law and order theme -

Trump, who has sought to make law-and-order a theme for his flagging re-election campaign, warned Monday he could send federal officers to New York and other Democratic-led cities to protect federal buildings and confront protests that he and lieutenants blame on "violent anarchists."

For the most part, protests across the country since the May 25 killing of George Floyd by a Minneapolis police officer have been peaceful and focus on racism and police abuse.

Two weeks ago the Department of Homeland Security began sending federal agents, including US Border Patrol officers, to Portland to fend off protests that have seen federal buildings in the city damaged with graffiti and broken windows.

On Monday though 15 mayors pushed back strongly in a letter to Barr and Homeland Security Acting Secretary Chad Wolf, saying they would not accept federal agents in their cities to deal with legal protests.

"Unilaterally deploying these paramilitary-type forces into our cities is wholly inconsistent with our system of democracy and our most basic values," they wrote.

"It is concerning that federal law enforcement is being deployed for political purposes," they said.

But Barr and  Wolf stressed Wednesday that the new deployments would partner with local law enforcement to focus on gun violence, which the mayors of Chicago and some other cities say they would welcome.

Wolf said there was a clear distinction with Portland. In Chicago, he stressed, the mission "is to protect the public from violent crime on the streets."