A 29-year-old man shot in the face early Monday morning in South Philadelphia and, 14 hours later, a 45-year-old man shot multiple times while on a Summerdale street, becoming the fourth and fifth men to be killed in the city since Saturday night.

During the bloody interval, at least 12 other people were wounded in separate shootings since Saturday night, including a man critically injured in a barbershop shooting Monday afternoon, authorities said.

In the latest fatal shooting, the 45-year-old man, whose name was withheld, was gunned down shortly before 5 p.m. while on the 1000 block of Alcott Street. Medics took him to Einstein Medical Center, where doctors pronounced him dead at 5:22 p.m.

The murder weapon was not recovered and police reported no arrests.

Monday's other homicide happened in South Philadelphia. Police officers called to the 2800 block of South Seventh Street about 2:45 a.m. found the 29-year-old with a gunshot wound in the face in a second-floor bedroom. Medics pronounced him dead seven minutes later.

The victim's 26-year-old brother told police he had been playing with a gun when it discharged, Chief Inspector Scott Small told reporters.

Small said investigators didn't yet know whether the shooting was intentional. The brother was taken to the Homicide Unit for questioning.

Meanwhile, police on Monday identified three people killed in the city over the weekend, and said their assailants remained at large.

The first of the weekend homicides happened about 8:45 p.m. Saturday, when 32-year-old Kareem T. Ali was shot on the 1700 block of West Jefferson Street in North Philadelphia, police said.

Ali, of the city's Ludlow section, was taken to Hahnemann University Hospital, where he died at 9:46 p.m. No motive was known.

Then, about 12:10 a.m. Sunday, 29-year-old Tyrell Boggs was shot on the block where he lived, the 3400 block of Braddock Street in Kensington.

He was pronounced dead at 12:22 a.m. from gunshot wounds to his chest. Police said the shooting apparently stemmed from an argument.

And about an hour and a half later, 39-year-old Robert Ostiguin of Tacony was fatally shot on the 6600 block of Essington Avenue in Southwest Philadelphia. Officers responding to a report of gunshots shortly after 1:45 a.m. found Ostiguin propped against a motorcycle at a BP service station there. He was pronounced dead there at 2:07 a.m.

A Philadelphia street-racing group claimed that the shooting stemmed from a street race and posted a video purportedly showing the incident on its Facebook page Sunday night.

In the five-hour span during which Boggs and Ostiguin were slain, police said, at least eight other people also were shot, including three who were critically wounded.

The violence continued into Monday.

On Monday afternoon, a 54-year-old man was shot once in his nose while inside a barbershop on the 1800 block of South 60th Street in Southwest Philadelphia, police said.

He was hospitalized in critical condition. Details of the shooting weren't immediately available.

Earlier in Southwest Philadelphia, another man was critically wounded when he was shot during a carjacking near 60th Street and Woodland Avenue, police said.

The 31-year-old man got out of a 2006 Pontiac Grand Prix when another man tapped on the window about 12:25 a.m. Monday, police said. The two began fighting, and the second man fired several shots before getting into the car and driving away, police said.

An officer took the victim to Penn-Presbyterian Medical Center for treatment of gunshot wounds to his leg and abdomen. A man who was with the victim was unharmed. The Grand Prix was found unoccupied a few blocks from the scene.

That followed a shooting Sunday night in which two people were wounded when someone began firing into the 2006 Ford Taurus they were in on the 500 block of North Sixth Street near Northern Liberties.

A 28-year-old man was shot in his right arm and buttocks; a 23-year-old woman was shot in her right thigh. Both were taken to Hahnemann in stable condition after the 10:45 p.m. Sunday.

Police said a 28-year-old man had been identified as a suspect. Investigators were still looking for him Monday morning.

No arrests have been announced in any of the shootings.

ebabay@philly.com 215-854-2153 @emilybabay