Teheran: Police said they received calls for emergency help after a man was stabbed in Rockford on Wednesday at 1.15 pm.

Four people were killed and seven others injured in a stabbing attack in a residential area in Northern Illinois on Wednesday afternoon.

Police Chief Carla Redd told a news conference in Rockford, about 80 miles northwest of Chicago. A suspect has been detained in the attack, whose motive is unclear, he said. Officials said that three people died on the spot while the fourth person died while undergoing treatment at the hospital. Seven injured people were taken to area hospitals where their condition is critical.

Police, who have not named the suspect, said he is a 22 year old man. They claimed that they were not looking for anyone else in the attack. Chief Redd told the media conference that they do not believe any other suspects are at large at this time.

A 15 year old girl, a 63 year old woman and two men aged 49 and 22 were among the dead, police said. A US Postal Inspection Service spokesman said a mail carrier was among the dead