The Chicago Police Department warned its officers Monday about gangs armed with high-powered weapons, after three people were shot to death over the weekend and two cops were targeted in an ambush last week.

Anthony Guglielmi, a police spokesman, said three people who were killed in shootings Sunday were all members of the same street gang. Two of them died while attending a memorial for the earlier victim.

A shooting in the early morning hours on Sunday left one man dead, and the two others were killed and eight people were injured in a spray of more than two dozen shots from two guns while attending a makeshift memorial for him. Police said they believe the victims were all shot by members of a rival street gang in the same neighborhood on Chicago's southwest side – Brighton Park.

Police increased patrols after the morning shooting of 26-year-old Daniel Cordova, who was found dead between parked cars in the Brighton Park neighborhood. The other shooting happened about a block away. The names of the other victims were not immediately released.

Given the very real possibility that the gang war has not played itself out, the department has saturated the same area with officers and tactical teams, Guglielmi said. It also has issued a warning about gunmen with weapons powerful enough to pierce bullet-proof vests.

Meanwhile, prosecutors said Monday that a reputed gang member sprayed a police van with more than two dozen rounds from an assault rifle after mistaking the vehicle and plainclothes officers inside for rival gang members. Authorities arrested the alleged driver in the ambush, Angel Gomez, but not the shooter. The shooting occurred in the Back of the Yards neighborhood.

Guglielmi said the incident in which two officers were shot while sitting in a car does not appear to be connected to the bloody gang feud that erupted Sunday. Combined, however, they are the latest examples of what they have seen as a greater willingness of arm themselves with weapons most associated with soldiers in battle.

At the scene of the second shooting alone, Guglielmi said that more than two dozen shell casings were recovered, with police believing that there were two people firing the weapons.

"We believe it was related to the memorial, a number of the people there knew the victim, and the rival gang observed that and took advantage," he said.

No arrests have been made in the suspected weekend-gang shootings.

The Associated Press contributed to this report.