Woman attacked and robbed on Muni bus in SF

A 8 Bayshore Express bus picks up passengers on the corner of Fourth and Market streets. A 8 Bayshore Express bus picks up passengers on the corner of Fourth and Market streets. Photo: Michael Macor, The Chronicle Photo: Michael Macor, The Chronicle Image 1 of / 43 Caption Close Woman attacked and robbed on Muni bus in SF 1 / 43 Back to Gallery

A woman riding a Muni bus near Union Square in San Francisco on Thursday afternoon found herself surrounded by a group of women who began to harass her before beating her and fleeing with her phone, officials said.

The 30-year-old victim was on the 8-Bayshore line bus near Kearny and Market streets about two blocks from Union Square shortly before 5 p.m. when the assault and robbery occurred, according to the San Francisco Police Department.

Four women, estimated to be 18 to 21 years old, surrounded the woman and began to harass her, police said.

The victim tried to use her phone to call police, but the four attackers began punching her, according to police.

One of the women snatched the victim’s phone, and the four got off the bus when it stopped and ran away, according to police. No arrests were made.

“We are working with SFPD as they fully investigate the incident,” Muni spokesman Paul Rose said. “We will turn over any video we may have and provide any other information to ensure they can make an arrest.”

Filipa Ioannou is a San Francisco Chronicle staff writer. Email: fioannou@sfchronicle.com Twitter: @obioannoukenobi