One man was killed and another was wounded early Sunday when a robber opened fire at a Montclare neighborhood restaurant on the Northwest Side.

About 2:50 a.m., the suspect, who was wearing a ski mask, robbed the fast food restaurant at gunpoint in the 7100 block of West Diversey, according to Chicago Police. Two men, ages 19 and 22, were shot while trying to stop the robbery.

The younger man, Jaime Arceo, suffered a gunshot wound to the right shoulder and was taken to Illinois Masonic Medical Center, where he was pronounced dead at 5:04 a.m., according to police and the Cook County medical examiner’s office. He lived in west suburban Elmwood Park.

The older man was shot in the back and was taken to Loyola University Medical Center, where his condition was stabilized, police said.

The robber ran from the scene after taking money from the register, police said.