The gun violence in one South Side Chicago neighborhood that left seven dead in a 12-hour period was mostly due to gang conflict, Police Superintendent Eddie Johnson said Friday.

On Thursday afternoon, four people were fatally shot in or near a restaurant after a man approached and opened fire. Two men were found dead from bullet wounds inside the restaurant. A third person was found unresponsive outside the restaurant. A fourth man who sustained gunshot wounds was found unresponsive a block away.

Two people were killed late Thursday when a vehicle pulled alongside a van in the city’s South Shore neighborhood. A man and woman were shot, the Chicago Police Department (CPD) said, and the van crashed into a pole.

“I’m angry and sick,” Johnson said during a news conference. “You have my promise that CPD will utilize the full weight of our resources to go after the individuals responsible for yesterday’s incidents.”

Johnson said investigators have determined most of the victims were targeted and had known gang affiliations. He added the woman’s killing wasn’t gang related.

Johnson says the gun violence in one South Side neighborhood that left seven dead in a 12-hour period was mostly due to gang conflict.

From Jan. 1 to April 2, the city has seen over 143 homicides, putting it on course to surpass the gruesome number of deaths last year. Johnson has called for increased governmental support in putting away repeat offenders, and though CPD’s strategic subject list — which is comprised of mostly gang members and repeat offenders — has helped officers identify who may commit crimes or who may be killed, the rate of violence is still something that officers are trying to understand and appropriately react to.

Johnson said Friday there will be a heavy and aggressive police presence in the South Shore neighborhood until the perpetrators of Thursday’s violence are in custody.

Police said a man and woman were fatally shot late Thursday when a vehicle pulled alongside a van and a person inside opened fire.

On Thursday afternoon, four people were fatally shot in or near a restaurant after a man approached and opened fire.  Before that, a 26-year-old pregnant woman was found in a home shot to death.

Johnson said there will be a heavy and aggressive police presence in the South Shore neighborhood until the perpetrators of Thursday’s violence are in custody. He added coordinated police operations will target the people who are driving the violence in the neighborhood and where retaliatory violence may occur.

“You lose count of the shootings after a while,” Kyra Carr, who lives a few blocks away and said she heard the gunfire, told the Chicago Sun-Times. “But seven bodies in a day. Crazy. Something is wrong.”

The Cook County medical examiner’s office identified three of the victims as brothers Raheem and Dillon Jackson, ages 19 and 20 respectively, and 28-year-old Emmanuel Stokes. The identity of the fourth victim was withheld pending notification of family.

The Chicago Tribune reports the Jacksons’ 72-year-old grandmother, Georgia Jackson, said the two went to the restaurant to get food and to see their mother, who works there. She said their mother called her about the shooting.

“She only said one at first but when I got here they said they found the other,” Georgia said.

Also on Thursday, about a mile from the restaurant, the body of 26-year-old Patrice L. Calvin was discovered in a home. The medical examiner’s office says Calvin, who was four months pregnant, suffered a gunshot wound to the head.

Johnson said the woman likely knew her killer, and her death wasn’t gang related.

No arrests have been reported by police.