Customers, staff robbed at gunpoint inside River North diner

Customers and staff were robbed at gunpoint inside a River North diner early Thursday morning. 

Chicago police said three men armed with guns entered Griddle 24, at 334 W. Chicago Ave. at the northeast corner of the intersection with Franklin Street, at 3:15 a.m.

Police said the group demanded and took money from the cash registers, and then targeted personal property from four people in the diner. The armed men also hit a 23-year-old man in the head during the incident. 

The man was taken to Northwestern Memorial Hospital in good condition.

Sources told CBS News Chicago the 23-year-old victim was an employee, and the other victims were customers at the diner. 

No arrests had been made as of later Thursday morning. 

Police are investigating.