CHICAGO (CBS) — With 24 people shot within 24 hours from Thursday into Friday, Chicago police were worried about a potentially bloody 4th of July holiday weekend.

There were 72 murders in Chicago in June, and for the entire year, the city has had more than 300 killings, a 50 percent spike over the first half of last year. Every weekend in June saw at least 39 people shot.

Police Supt. Eddie Johnson’s frustration with the continuing bloodshed was obvious as he discussed the department’s deployment strategy for the Independence Day weekend.

“You can’t predict what’s in the mind of the repeat offenders that want to keep wreaking havoc in our neighborhoods. It’s unacceptable. I’m sick and tired, and I know the people that live in those communities are tired of it,” he said.

Illinois State Police Director Leo Schmitz also expressed his outrage over the seemingly unending wave of gun violence across Chicago.

“I’ve said this before, and I’ll say it again, our number one goal is to save lives,” Schmitz.

Johnson and Schmitz met with reporters on Friday to discuss the holiday weekend. They said they’re working together to put more officers on the expressways, in the air, on foot, and on bikes – especially where large numbers of people will gather. In all, more than 5,000 law enforcement officers from CPD, ISP, and the Cook County Sheriff’s office will be on patrol over the weekend.

“We’re making it abundantly clear that we will not tolerate violence,” Johnson said.

Last year, 10 people were killed and 55 were wounded over the long Independence Day weekend, and the 4th of July holiday is often one of the bloodiest weekends of the year.

Johnson reiterated that about 1,400 people in Chicago are responsible for most of the gun violence in the city. The department maintains a watchlist of sorts, called the “strategic subject list,” which relies on an algorithm to try to predict who is most likely to be involved in a shooting – either as the shooter or victim – by analyzing data such as gang affiliations, criminal records, past shootings, and previous contact with police.

Although police know most of the shootings in the city are tied to someone on that list, Johnson has stressed police can’t arrest anyone on the list until they actually commit a crime.