CHICAGO (CBS) — Two people, including an off-duty Chicago police officer, were taken to the hospital after they were involved in a fight with three strangers after leaving a nightclub in the River North neighborhood.

Police said two off-duty officers and a female companion were walking near LaSalle and Hubbard around 2 a.m., when they were approached by three strangers, and got involved with a fight.

One of the off-duty officers, a 32-year-old man, suffered injuries to his face. He was treated and released at Northwestern Memorial Hospital, police said. The other off-duty officer, a 25-year-old man, was not injured.

The woman who was with them was not involved in the fight, but fainted, and was taken to Northwestern.

It was not clear what prompted the fight.

Police said responding officers arrested two of the three suspects. Charges were pending Friday afternoon.

Area Central detectives were investigating.