OKLAHOMA CITY - Police are investigating after a truck driver was shot by a security guard Friday morning at a southwest Oklahoma City Truck Stop. 

According to authorities, the shooting was at T A Truck Services near Interstate 40 and South Council Road. 

Police said a security guard and a truck drivers got into an altercation over a parking issue. When the argument escalated, the security guard shot the truck driver.

The driver was hit once and taken to OU Medical Center in serious condition. 

The security guard is being questioned by police. 

This is a developing story.