A 70-year-old woman was hospitalized Sunday, after a fellow bus rider punched her in the face after their bags made contact.

According to the San Francisco Police Department, the altercation went down on a Muni bus near the intersection of Stockton and Washington Streets on Sunday at around 12:40 in the afternoon.

Police say that the victim was riding Muni when her bag bumped into the bag of a fellow rider.

That rider, a man witnesses say was between 65-70 years in age, reacted to the bump by striking the woman "in the face with a closed fist several times," police say.

The attacking man then hopped off the bus and fled north on Stockton, police say.

The victim was transported to an area hospital for treatment of "redness and swelling to her right eye," police say, characterizing her injuries as non-life-threatening. Her attacker, police say, remains at large.