At 10:15 p.m. Thursday, the two sisters - one from Lansing, Mich., and the other from Grand Rapids, Mich. - returned to the bed and breakfast in the 100 block of East 35th Street, where they had checked in.
Three black teens with guns approached the two women, knocking one of them to the ground. The assailants hit the other woman in the head with a gun, said metro police spokeswoman Judy Pal.
Both women were taken to Memorial University Medical Center. As of Friday night, neither were listed on the hospital's registry, said Memorial spokeswoman Becky Keightley.
The men then fled in the women's red Dodge Caliber.