Trump said Johnson and Pritzker "should call for help."
On Wednesday, Mayor Johnson thanked police after the holiday weekend passed without any homicides.
Memorial Day weekend closed out with a "teen takeover" at 57th Street Beach in Hyde Park.
CPD said 53 people were arrested in connection with Monday's "teen takeover." Thirteen people, including eight juveniles, were charged with felonies.
The shooting happened around 10 p.m. Monday in the 1600-block of East 55th Street. The three teens injured are in good condition.
Five Chicago police officers were struck by a driver while dispersing a "teen takeover" early Sunday, officials said.
All five officers were initially taken to local hospitals and were expected to be OK.
The persistent problem with large teen gatherings that often turn dangerous or destructive is continuing to spur debate on how best to combat the issue.
Johnson Wednesday talked about the need for accountability, but pushed back on giving police more tools to respond.
Johnson had mixed messages about addressing so-called teen trends. While he said those who break the law should be arrested, he said arrests aren't the answer and neither is a stronger curfew law.
"Accountability certainly matters. We will not accept any act that places Chicagoans in danger. We continue to call on parents, guardians and all the adults of this city to stay aware of where their children are," Johnson said. "The accountability mechanism is, if people break the law, they should be arrested."
He went on to say, "There were 15 arrests on Sunday. It did not stop the trend from happening on Monday, right?"
The mayor's comments frustrated Alderman Brian Hopkins, who chairs the Public Safety Committee.
"To say it doesn't work because someone got arrested one day and a person repeated that crime the next day, that's nonsense, too. That's like saying, 'well, we shouldn't have speeding laws because people speed and get tickets.' And then the next day someone else was speeding," Hopkins said. "That was a particularly violent event. So it doesn't bode well for the coming summer. I think we're going to be in for a pretty rough time."
Hopkins continues to champion a modified curfew law to give police more options to respond to teen gatherings, which he fears will continue to happen this summer.
"We're asking for the flexibility to use the curfew as a dispersal tool, and to be able to use it any time a teen takeover happens. We can currently use it after 10 p.m. But if a teen takeover starts to happen at 6 p.m., we should be able to use it then," Hopkins said.
But the mayor disagrees.
"What we have seen, though, in other places, these aggressive tactics have not necessarily deterred these gatherings into taking place. In fact, in too many instances, they ultimately exacerbate the situation," Johnson said.
There is also growing support for more parental accountability, with a new ordinance reportedly in the works.
"Young people who stand on cars and twerk need to be held accountable, along with their parents. Yeah, it's about accountability. You don't get to get off because you're a parent," 20th Ward Alderman Jeanette Taylor said.
Mayor Johnson declined to say if he would support a parental accountability law without seeing what it look like.
But he also had a message for kids who find themselves caught up in a gathering that gets out of hand: Go home.
"Let's just be honest, this is a drag on the positive impact that my administration has had in building safer and more affordable communities," Johnson said.
INTERACTIVE SAFETY TRACKER | Track crime and safety in your neighborhood