A woman was severely injured after two people she was arguing with on a bus attacked her and left her in the street in the Mission District.

The 55-year-old woman was arguing with a man and a woman on Muni's 9-San Bruno bus around 7 p.m., Thursday evening, according to witnesses. All three people got off the bus on the 300 block of Potrero Avenue and the argument spilled onto the sidewalk. Witnesses in the street say they heard yelling and the woman was found unconscious on the ground.

According to SFGate the woman was taken to San Francisco General with a life-threatening brain injury.

The two attackers fled on foot and police have yet to make any arrests.