CHICAGO (CBS) — Two men held up a Bridgeport diner early Friday, taking the cash register, and shooting a security guard.

Shortly after 3 a.m., two masked men walked into Kevin’s Hamburger Heaven, a 24-hour diner at the corner of Pershing Road and Wallace Street, and announced a robbery.

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Most employees and customers ran to a bathroom and hid, but a security guard at the restaurant began struggling with one of the robbers, who shot the guard in the buttocks.

The robbers then stole the cash register, before driving away.

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The security guard was taken to John H. Stroger Jr. Hospital of Cook County, where he was listed in good condition.

The diner reopened a few hours after the robbery. Workers replaced the stolen cash register with another one.

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No one was in custody as of Friday morning.