Six people have Grayson  Prestonbeen hospitalized after they were hit by a car inside a Washington, D.C., hospital parking garage, officials said. 

DC Fire and EMS initially said in a tweet that five pedestrians were struck at the MedStar Georgetown University Hospital parking garage on Thursday afternoon. The hospital later said it was treating a sixth patient related to the incident, DC Fire and EMS said. The patients were being treated at the hospital's emergency room and the driver was also being evaluated, officials said. 

Officials confirmed to CBS News that at least one adult woman was not conscious or breathing. 

Fire officials have not offered any additional details on the condition and identity of the driver or victims. It is unclear what caused the crash.  

This is a developing story. Updates will be posted.