(CNN) Across three states, at least 28 people were shot in three separate incidents over the weekend.

Law enforcement agencies in all three incidents have not arrested or named any suspects in the separate shootings as of Monday morning.

Investigators have asked witnesses and those with information or video to reach out to authorities.

13 people were shot in Chicago at a memorial party

In Chicago, 13 people were shot overnight while attending a party to commemorate the life of a shooting victim who died earlier this year, Fred Waller, chief of the Chicago Police Bureau of Patrol said during a Sunday morning press conference.

The shooting happened after a dispute broke out at the party around 12:35 a.m. Sunday in the 5700 block of S. May Street, police said.

Police respond to a shooting on S. May St. in Chicago early Sunday morning.

"Shots were fired within the residence, which caused everyone to start to leave," Waller said.

The victims, ranging in age from 16 to 48, suffered various injuries and were transported to area hospitals for treatment. Four victims were in critical condition Sunday, according to the Chicago Police Major Incident Notification website.

No suspect information was available but police say two persons of interest were taken in for questioning.

Police also arrested a man seen fleeing the area of the shooting who has since been charged with unlawful use of a weapon by a felon, according to a Chicago Police Department press release. Police could not confirm that his arrest was in connection with the shooting. He's scheduled to appear in court on Monday.

Sunday afternoon, Chicago Mayor Lori Lightfoot admonished the violence occurring in her city. "This kind of violence is simply not going to be tolerated in our city," Lightfoot told reporters after visiting shooting victims and family members.

Our hearts are with the 13 individuals whose lives were significantly harmed after gunmen opened fire at a memorial gathering last night. — Mayor Lori Lightfoot (@chicagosmayor) December 22, 2019

She urged anyone with information to come forward, saying someone "inside that room knows exactly who the shooters were."

7 people shot while waiting to get into a Baltimore lounge

Within hours of the Chicago shooting, seven people were shot and injured as they waited to get into a lounge in downtown Baltimore.

As many as four suspects are being sought in the shooting, Baltimore Police Col. Rich Worley said Sunday.

Worley said two shooters exited a car near the lounge just after 2 a.m. Sunday and began firing on those waiting in line.

One man had a handgun while a second had a rifle. A total of nineteen shots were fired, Worley said. Those injured, ages 17 to 27, were taken to local hospitals for treatment.

The car the suspects arrived in was recovered but had been set on fire, according to Worley.

One person was killed and seven others were injured in a shooting in Minnesota within hours of the other two shootings, police said.

A 19-year-old man dies in Minnesota shooting

Shortly after midnight Sunday morning, police responded to a shooting in the parking lot of the Dala Thai Restaurant and Banquet Hall in Spring Lake Park, about 12 miles north of Minneapolis.

One man is dead and 7 others are injured in a shooting outside Minneapolis.

Multiple agencies responded to the shooting and discovered victims ranging in age from 19 to 38 suffering from gunshot wounds. Chai Yang, 19, was killed in the shooting while seven other shooting victims suffered from non-life threatening injuries, according to a press release from the Anoka County Sheriff's Office.

Authorities are asking any bystanders of the shooting who may have video of the incident to reach out to investigators, the release said.