About two dozen heavily armed law enforcement officers stormed a home in Chicago's southern suburbs Wednesday to free four hostages and capture two suspects, ending a 20-hour standoff that police say began as a robbery attempt.

Two women and two children were freed midmorning from the home in the small city of Harvey without a shot being fired, Cook County Sheriff Tom Dart told CBS News.

The standoff began at 12:45 p.m. Tuesday when police in Harvey responded to a neighbor's report of a possible burglary at the home. Two officers were wounded in an initial exchange of gunfire, and the two suspects barricaded themselves inside the home with eight captives. Four children among them were freed overnight after hours of talks. No one else was injured throughout the ordeal.

Dart said negotiators were in "constant contact" with the hostage-takers throughout the night but that the talks reached a stalemate late morning and a decision was made to storm the house. Negotiators still had the suspects on the phone as the officers used a battering ram on an armored truck to break down the door and sweep in.

Officer Darnell Keel, an 18-year veteran of the police force, will undergo surgery for a broken arm, Howard said. A second officer suffered a graze wound to an arm.