Three major U.S. cities struggling to curb a surge in gun violence collectively had at least 64 people wounded and 12 dead, including a 7-year-old girl, in multiple shootings this weekend, according to police.

The shootings in New York, Philadelphia and Chicago came as all three cities have seen sharp increases in the numbers of shootings in 2021.

In Chicago, at least 46 people were shot between 5 p.m. on Friday and Sunday afternoon, four of them fatally, according to the Chicago Police Department. According to police incident reports reviewed by ABC News, 23 of the shootings occurred over just a 4 hour period between 12:26 a.m. and 4:30 a.m. on Sunday.

Around 3 p.m. on Sunday, a 7-year-old girl was killed and a 6-year-old girl was seriously wounded when someone opened fire on a parked vehicle they were sitting in the Belmont Central neighborhood on the city’s Northwest Side, police said. The 7-year-old was shot in the chest and later died at a hospital.

The 6-year-old girl was also shot in the chest and right armpit and was in serious but stable condition at Loyola University Medical Center Sunday evening, police said.

Police were working to identify the shooter or shooters involved in the incident. Police did not comment on a possible motive.

More than 250 children have been shot and 32 killed in Chicago this year, according to police data obtained by ABC station WLS.

Prior to this weekend, more than 2,123 people had been shot in Chicago this year, which is a 12% increase from the same time period in 2020, according to police department crime statistics. Before this weekend, Chicago has recorded 478 homicides, a 2% increase over last year at this time.

A shooting that occurred Friday night on the Eisenhower Expressway on the city’s West Side left one person dead and two others critically wounded. Illinois State Police said the three victims were in a car on Interstate 290 when a vehicle pulled up alongside them and someone inside opened fire.

In a shooting around 12:36 a.m. on Sunday, a woman and three men, ranging in age from 30 to 45, were shot and wounded as they stood outside a building in the Grand Crossing neighborhood on the city’s South Side, police said. The victims told police they did not see where the shots came from, according to an incident report.

Just after 2 a.m. Sunday, three teenagers, the youngest 15, were shot and wounded while standing outside a gas station in the city’s Chatham neighborhood on the South Side, police said. About 20 minutes later, three other people were shot while traveling in a car in the Mayfair neighborhood in northwest Chicago, police said.

The shootings in Chicago followed last weekend’s violence, which saw 73 people shot in the city, 11 fatally.

Chicago police Officer Ella French was among those gunned down last weekend when she and her two partners pulled over a car for having expired tags. One of French’s partners, a 39-year-old officer, was shot in the eye and remains in a hospital in critical condition with a bullet lodge in his brain, police said. Two brothers were arrested and charged in French’s slaying.

The Chicago Police Department has launched several programs this summer in an attempt to curb shootings and reduce the number of illegal guns on the streets.

Last month, Police Superintendent David Brown assembled a team of 50 officers to target gun traffickers, straw buyers, unscrupulous licensed firearms dealers and anyone who facilitates the flow of illegal guns into the city of Chicago.

11 people shot, 5 fatally in Philadelphia

Entering the weekend, 1,333 people had been shot in Philadelphia this year, a 19% increase from the same period a year ago, according to police department crime statistics. By the end of Friday, the city had recorded 329 homicides, a 26% increase from the same time period in 2020, the data shows.

Eleven more people were shot in Philadelphia over the weekend, five fatally, according to police.

“We need to stop this,” Philadelphia resident and retired Marine Jamal Johnson told ABC station WPVI in Philadelphia.

The weekend gun violence came as Johnson and a group of supporters are marching to Washington D.C. to draw attention to the escalating number of shootings and killings in their city. Johnson calls his action the “Stop Killing us March” and hopes to meet with members of the Congressional Black Caucus when he reaches the U.S. Capitol later this month.

“I would personally like them to encourage (Philadelphia) Mayor (Jim) Kenney to declare a state of emergency in Philadelphia due to gun violence,” Johnson said. “Most of all to save the lives of our children.”

Kenney said during a news conference last month that the city allocated over $150 million in its fiscal year 2022 budget to address gun violence. He said he has spoken to President Joe Biden “on the urgent need for new and enhanced approaches” to combat the problem.

“An emergency or disaster declaration would not change the direction of this work,” the mayor said.

In the weekend homicides in Philadelphia, a 25-year-old man was shot multiple times on a street in the Tioga-Nicetown neighborhood of North Philadelphia about 9 p.m. on Saturday, police said. The victim, whose name was not released, was taken to Einstein Medical Center and pronounced dead.

Around 5 a.m. Saturday, a man was found shot in the parking lot of a gas station in the Wynnefield neighborhood in the northwest part of Philadelphia police said. The man, who was not named by police, was pronounced dead at a hospital.

A 30-year-old man died after being shot multiple times around 12:44 a.m. Saturday on a street in the Grays Ferry neighborhood of South Philadelphia, police said. And a 46-year-old man died after being shot in the chest around 1:36 a.m. Saturday in the parking lot of the Rite Aid in southwest Philadelphia.

No arrests have been made in any of the homicides, police said.

More than 1,100 shot in New York City this year

In New York City, where more than 1,100 people have been shot this year, an 11% increase from a year ago, police said 15 more people were shot, three fatally, in 11 separate incidents on Friday night alone. The three homicides occurred in just 4 1/2 hours.

The deadly violence started about 12:20 a.m. on Saturday when police discovered a man lying next to a motorcycle with a bullet wound to the head in the Woodlawn neighborhood of the city’s Bronx borough, according to the New York Police Department. The victim, whose name was not immediately released, was pronounced dead at the scene, police said.

About 40 minutes later, a 38-year-old man was shot in the Far Rockaway neighborhood of the city’s Queens borough, police said. He was taken to a hospital, where he was pronounced dead.

Just after 4 a.m. on Saturday, a 27-year-old man was shot dead while standing on a street in the Morris Heights neighborhood of the Bronx, police said. The shooting also left a 23-year-old man wounded.

No arrests have been made in the New York homicides.

Among the non-fatal New York shootings, four men were wounded just after midnight Saturday at the Louis Armstrong Houses in the Bedford-Stuyvesant neighborhood in the city’s Brooklyn borough.