Chicago Police are investigating an armed robbery at Kevin's Hamburger Heaven at Pershing and Wallace this morning.
Two men, one armed, walked into the restaurant around 3:10 a.m. and announced a robbery.
One of the men got into a struggle with a security guard and the security guard was shot.
Darcell Igbo was in the diner during the robbery.
"He came in and ran right past the security guard and the security guard grabbed him before he could get past him. Then I heard the shot go off," Igbo said.
The two men then took the cash register and fled in a vehicle.
The 36-year-old security guard was taken to Stroger Hospital with a gunshot wound to his backside and he is listed in good condition, Chicago police said.
Nobody else in the restaurant was injured.
Chicago police continue to investigate.