At least 13 people have been wounded, five critically, in two shootings that erupted over a span of 12 hours at homeless encampments in Minneapolis with the city’s mayor saying he wouldn’t be surprised if they are connected.

The shootings on Monday marked the fourth and fifth mass shootings to occur in Minneapolis in the past three weeks, including one on Aug. 27 at Annunciation Catholic School that left two children dead and 21 people injured.

“This is tragic. It’s horrible. It’s unacceptable, and, sadly, it’s not surprising,” Mayor Jacob Frey said at a news conference early Tuesday.

Minneapolis Police Chief Brian O’Hara said the city’s latest mass shooting unfolded Monday night at a notorious homeless encampment in southeast Minneapolis, in which eight people were shot and an estimated 30 shots were fired.

“Here we are yet again in the aftermath of a mass shooting. This is not normal,” O’Hara said.

O’Hara said the shooting at the homeless encampment on South 28th Avenue and East Lake Street occurred around 10 p.m. local time. He said an officer working at a Target store nearby was approached by multiple people “running and telling him that there was gunfire at the encampment.”

“The officer exited the store and heard gunfire coming from the area of the encampment,” O’Hara said.

Upon arrival, officers found five people wounded, including two people, a man and a woman, discovered inside tents suffering from bullet wounds to the head, O’Hara said. He said three other gunshot victims showed up at hospitals on their own.

O’Hara said at least four of the victims had life-threatening gunshot wounds.

The chief said multiple shell casings were recovered from the scene, leading investigators to believe that someone inside the encampment exchanged gunfire with the shooter who targeted the encampment.

O’Hara said that in addition to the shooting, a fire broke out in one of the tents while police were on scene and that that firefighters were called to extinguish the blaze.

No arrests have been announced in the shooting.

O’Hara said detectives are investigating the possibility that the shooting is connected to earlier gunfire at a nearby homeless encampment that left five people injured, including one in life-threatening condition. He said the earlier shooting occurred just after 11 a.m. near the intersection of East Lake Street and Stevens Avenue.

“While the investigation is still very, very preliminary, that is certainly something that we can’t rule out, and, of course, it’s something that we are considering,” O’Hara said.

Asked about the possible connection between the two shootings, Frey added, “We don’t know for sure, but I wouldn’t be surprised.”

Frey said the city has been trying for months to clear the homeless encampment at South 28th Avenue and East Lake Street, the scene of Monday night’s shooting. He said the encampment is on private property and that the city’s attempts to clear it have been met with resistance by the owner of the property.

“These homeless encampments are not safe either for the people that are in them, nor are they safe for the surrounding neighborhood. With this particular one, we’ve been saying this for months. We have been met with resistance for trying to clear this particular encampment,” Frey said.

In addition to the Annunciation Catholic School shooting, in which the suspect, 23-year-old Robin Westman, died by suicide, Minneapolis police investigated an Aug. 26 mass shooting that left one man dead and five other people wounded in southwest Minneapolis.

At the time, O’Hara said the shooter walked up to a group of people standing at the corner of East 29th Street and Clinton Avenue South and unleashed a barrage of at least 30 shots with a high-powered rifle before fleeing.

No arrests have been announced.

ABC News’ Jessica Gorman contributed to this report.