Shootings and other violence during the extended July 4 weekend have left at least 33 people dead across the US, including 11 in Chicago, and injured dozens more nationwide, authorities said.

July 4 is historically one of the nation’s deadliest days of the year.

A flurry of shootings around the holiday a year ago left more than a dozen people dead and over 60 wounded.

And a year before that, seven people died in a mass shooting at July 4 parade near Chicago.

Violence and mass shootings often increase in the summer months, with more people gathering for social events, teens out of school and hotter temperatures.

In Chicago alone, 11 people had been killed and 55 wounded in shootings as of Friday morning during the extended July 4 weekend, the Chicago Sun-Times reported.

The violence included a mass shooting on Thursday that killed two women and an eight-year-old boy.

The recent violence “has left our city in a state of grief,” Mayor Brandon Johnson said.

A community rally was planned for Friday evening, and the city will beef up police presence over the weekend, Mr Johnson said in a statement.

“We are devastated by the recent violence that has left our city in a state of grief and we extend our heartfelt condolences to the families and communities impacted by these recent events,” he added.

Eight people were wounded in Chicago’s Little Italy neighbourhood shortly after midnight on Friday.

Around 90 minutes later, a shooting in the city’s Austin neighbourhood injured six.

Police said preliminary findings suggest the separate shootings involved an exchange of gunfire between two people who then fled.

Recent violence at a popular Lake Michigan beach in Chicago prompted officials to close it early each night through the holiday weekend as a precaution.

The 31st Street Beach has been the scene of recent stabbings and shootings.

In Huntington Beach, California, two people were killed and three others injured in an Independence Day attack less than two hours after a fireworks show ended, police said.

Authorities arrested a suspect after responding to reports of an assault with a deadly weapon on Thursday night.

In the north-eastern Ohio community of Niles, Police Chief Jay Holland said a 15-year-old male was in custody after a 23-year-old man was fatally shot on Thursday night at a July 4 party at a residence.

A 10-year-old girl, identified as Gracie Griffin, was fatally shot in a Cleveland neighbourhood, police said.

It is not yet known what sparked the shooting or if she was targeted.

A 19-year-old man was killed and six others were wounded in a drive-by shooting in Philadelphia on Thursday night.

The wounded, which included four juveniles, were being treated at hospitals for various injuries that were not considered life-threatening.

It is not known yet what prompted the shooting.

Three shootings occurred in the Boston area following the city’s July 4 celebrations, leaving one man dead.

The fatal shooting occurred about 1.30am on Friday in a park near Boston’s South End neighbourhood.

At about the same time, three other people were wounded in the city’s Jamaica Plain neighbourhood.

A third shooting at a gas station later left a victim with life-threatening injuries.

A 17-year-old male suffered a stomach wound in another shooting Thursday night in a condominium parking lot in East Bridgewater, Massachusetts.

In Connecticut, a woman was found shot in her car early on Friday and was pronounced dead at a hospital.

Police identified her as Shamyria Williams, 23, of Hartford.

Relatives told reporters they believed she had just left a July 4 party.

Police in Albany, New York, said six males ranging in age from 16 to 19 were being treated at a hospital for injuries that were not considered life-threatening after a shooting at a large gathering.

Police responded to reports of a shooting at a home around 12.15am on Friday.

None of the victims were found at the scene but police said they located evidence consistent with gunfire in the yard behind the residence and in the street.

One teenager who had been shot flagged down officers along a street a short time later, police said.

Four people were wounded in a shooting early on Friday outside a Tampa adult nightclub after an altercation between the club’s security guard and two men, police said.

The two men drove their car to the front of the Pink Pussycat Lounge and one of them shot the security guard with a handgun, police said.

The security guard underwent surgery at a hospital and was in stable condition.

Three other men suffered unspecified minor injuries. Police said both suspects were arrested and charged with several crimes.

In the Queens section of New York, an eight-year-old boy was fatally stabbed in an apartment in what police described as a domestic dispute.

Police said officers later fatally shot a 20-year-old man who held a knife to his 43-year-old father’s throat and refused commands to drop the weapon.

In High Point, North Carolina, a shooting at an unofficial fireworks display left one person dead after a large crowd had gathered in the parking lot of the city about 90 miles west of Raleigh, police said

The victim was identified as Keith Lynch, 32, of High Point.

Shootings at two St Louis-area July 4 gatherings left two men dead and five others injured, two critically, police said.

In West Virginia, Charles Speer, 42, of Kermit, died early on Friday after being shot multiple times following a physical altercation at the home of another man, state police said.

And a road-rage incident led to the fatal shooting of a 36-year-old man in Taneytown, Maryland, according to the Carroll County Sheriff’s Office.