Rivers Casino in Des Plaines was shut down for seven hours overnight, officials said.
A casino employee said the casino was closed from 2 a.m. to 9 a.m. due to "technical difficulties."
The employee refused to give more information, but other published reports say the security cameras shut down, causing the casino to close.
Calls to a company spokeswoman were not immediately returned.
Des Plaines Police Cmdr. Louis Wittmer said police assisted in helping people exit the casino around 2 a.m. Everything appeared to go smoothly as customers left and went home, he said.
"There were no incidents that were reported," he said.
Check back later at dailyherald.com for more details.