Ten people have been killed and four others wounded in separate incidents in four US cities over the weekend.

Two men and a woman were shot and killed and another man was wounded at a home in Philadelphia, Pennsylvania, on Sunday.

The three victims were shot in the head by a gunman, identified as 46-year-old James Elijah Dickson, who also shot another man in the arm.

Authorities said that Dickson pulled out a shotgun and opened fire at his home after an argument broke out, killing his brother and his brother's girlfriend, and another man.

In another incident in Seminole County, Florida on Sunday, a man killed his estranged wife and two young children before taking his own life, police announced.

Thirty-year-old Henry Ramone Brown was waiting in the trunk of Chericia Brown's vehicle, outside a Chili's restaurant for his wife, Seminole County Sheriff's officials said.

After his wife arrived, Brown stabbed her and then ran over her with his car. She was rushed to a hospital, but later was pronounced dead.

The killer then went to his apartment complex and after switching vehicles, he picked up the couple’s children and drove to Central Florida Regional Hospital where he confronted deputies.

Brown shot at the officers and ran from the hospital. Police later found him dead inside his car along with the two dead children aged 1 and 4.

Also in Milwaukee, Wisconsin, two men were shot dead and three others were wounded in separate shootings that took place late on Sunday night and early on Monday morning.

In one incident, Terry Giesler, 46, was shot at around 9:15 pm Sunday and in spite of the life-saving efforts by responders, he succumbed to his injuries.

Police said that a woman, 45, was wounded in the shooting and taken to a hospital.

At 10:20 pm on the same day, another man, aged 23, was shot dead in what was believed to be an altercation between the victim and a suspect.

In another shooting Monday morning, a 43-year-old Milwaukee man was shot and suffered a non-life threatening injury. Another man, aged 24, was also shot and wounded as he stood on a friend’s porch. He was hospitalized and in stable condition.

In yet another shooting on Saturday, a 12-year-old boy was fatally shot in Knoxville, Tennessee, after he went to an anti-violence basketball game held to honor his 15-year-old cousin, Zaevion Dobson, who was killed in a shooting in December, 2015.

Jajuan Hubert Latham was shot in the head while he was in a park in Knoxville just before 10 pm, police said Sunday.

At least 200 people were attending the event and Latham was shot after a gunfire erupted between a group of attendees and occupants of two passing vehicles.

"He was so hurt about Zaevion, he just had so many questions as to how it happened, did he feel it? Just so many questions," said Latham's mother Delandra Porter.

The US Centers for Disease Control and Prevention (CDC) has put the total number of domestic gun deaths at 1.5 million between 1968 and 2014.

According to the CDC, firearms are the cause of death for more than 33,000 people in the United States every year, a number that includes accidental discharge, murder, and suicides.