A man attacked a teenage girl on a Metro Transit bus in South St. Paul on Tuesday evening and she stabbed him in apparent self-defense, authorities said.

Police responded to a report of an assault on a Route 68 bus near Southview Blvd and 15th Avenue S around 7:30 p.m. Preliminary information indicates that the girl stabbed her assailant in the arm, said Metro Transit spokesman Howie Padilla.

The suspect was taken to Regions Hospital for noncritical injuries. The victim also sustained minor injuries. Their names have not been released.

Investigators interviewed the driver and fellow riders Tuesday evening, but a motive remains unclear.

No arrests have been made, but possible charges are pending.

Route 68 runs 16 miles from Inver Grove Heights to the St. Paul-Maplewood border.

The assault comes just two weeks after the brutal attack in Minneapolis that killed a 75-year-old man who asked a group of fellow passengers to lower their voices on a Metro Transit bus.

Shirwa Hassan Jibril, a respected Somali elder, died six days after a 23-year-old man followed him off the bus and struck him so hard that he fell and hit his head on the pavement.