2 women beaten, robbed by group of 15-20 people in SF

File photo of police squad car at night. Patrol car with lights flashing File photo of police squad car at night. Patrol car with lights flashing Photo: Ron Chapple, Getty Image Photo: Ron Chapple, Getty Image Image 1 of / 43 Caption Close 2 women beaten, robbed by group of 15-20 people in SF 1 / 43 Back to Gallery

An argument that started late Sunday night near Civic Center in San Francisco quickly escalated into a dangerous mob attack, as two young women found themselves beaten and robbed by a group of more than a dozen assailants, police said.

The victims, two women ages 19 and 20, were standing on the 1200 block of Market Street between Eighth and Ninth streets about a block from City Hall when the conflict began about 11:30 p.m., according to the San Francisco Police Department.

One of the victims got into an altercation with another woman, who was at the scene with a group of 15 to 20 men and women, police said.

As the conflict spiraled out of control, the men and women in the larger group jumped into the fray, punching and kicking both victims, before stealing their cell phones and purses, and scattering to flee on foot in all directions, according to police.

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The two victims were transported to the hospital for treatment, but their injuries are not life-threatening, police reported.

Police did not specify what prompted the altercation that sparked the attack. No arrests have been made.

Filipa Ioannou is an SFGATE staff writer. Email her at fioannou@sfchronicle.com and follow her on Twitter