According to E Online, production has halted on Transformers 3 after an extra was injured on set.

Hospitalised on Wednesday evening, the woman was not part of the stunt team but behind the wheel of a car when she was hit by an object, which caused her severe head injury. In the statement released, authorities report:

“Preliminary investigation revealed that shortly before 7 p.m, the movie crew was filming a stunt using numerous vehicles and drivers. During this stunt, an object struck a 2006 Toyota, hitting the vehicle, and then went through the windshield hitting the driver.”

On a less official note, fellow extra Blaine Baker told an ABC affiliate

“The vehicle was being towed by another vehicle. The cable between the two vehicles broke. It whipped around and sliced through the woman’s car and sliced through her skull, apparently.”

Production was suspended immediately as the extra, identified as 24-year-old Gabriela Cedillo, was airlifted to Loyola Medical Center where her condition was described as critical. With filming originally scheduled to continue today in Chicago’s Millennium Park, the shoot has since been cancelled while police investigate the situation.

It is unknown whether the incident will effect the planned 1 July, 2011 release date of Michael Bay’s latest pixel-fest.