(CNN) -- Hours after two robbery suspects shot at police and took eight people hostage, the standoff inside a suburban Chicago home continued early Wednesday .
Authorities got their first indication of trouble in the form of a 911 call about a robbery around 2:40 p.m. Tuesday (3:40 p.m. ET), said Harvey, Illinois, police spokesman Sean Howard.
Two officers responding to that call were injured by gunfire.
Sometime afterward, the suspects entered a home and took the hostages, according to Harvey police spokesman.
Law officers from all over Illinois then surrounded the residence and began the process of negotiating with the hostage-takers.
Throughout the night, the suspects released four children. Two adults and two children remained hostages late Tuesday night, Howard said.
Harvey Mayor Eric Kellogg wants residents to stay inside their own homes as police, who have blocked off nearby streets, deal with the situation.
Both wounded officers are at a local hospital. One of them was grazed by a bullet and is in stable condition, while the other is in good condition, according to Howard.
A city of about 25,000 people, Harvey is about 20 miles south of Chicago.
CNN's Greg Botelho contributed to this report.