Yet another armed civilian in the United States killed and injured several people, this time at a mall in Indiana, before an armed bystander fatally shot him and put an end to another installation in the series of mass shootings in the country.

The gunman was armed with a "long gun," Greenwood Police Department chief Jim Ison said at a news conference on Sunday, noting that he appears to have acted alone.

The shooting claimed the lives of three people and injured two others, officials have reported.

Police officers responded to reports of shots fired at the food court in Greenwood Park Mall in Greenwood, Indiana, at about 6 pm local time.

Those wounded in the shooting were hospitalized, with Ison adding at a second news conference that their condition was stable.

The victims included a male and four females, Ison said, not revealing which were dead or injured. Greenwood Mayor Mark Myers said in a statement later that among those injured was a 12-year-old girl who sustained "minor injuries".

The rampage came to an end when an armed bystander shot the gunman, officials have said. The bystander was in lawful possession of a firearm, which police Ison said he believed was a handgun. It is yet unclear if the assailant's firearm had been acquired legally or not though.

The bystander "was able to stop the shooter almost as soon as he began," the police chief said. He "appears to be cooperating fully."

Mayor Myers said in a second statement that the gunman's identity and motive were still unknown, though he noted that "we do know that someone we are calling the 'Good Samaritan' was able to shoot the assailant and stop further bloodshed. This person saved lives tonight."

The term, “Good Samaritan” came from a Bible passage of a man from Samaria who stopped on the side of the road to help a man who was injured and ignored.

I cannot believe we live in a world where the term can equally apply to someone *killing* someone… my God. https://t.co/0a3sgzejzD

— Justin Kollar (@kollarjustin) July 18, 2022

Greenwood Park Mall's parent company, Simon Property Group, just like many others like it, stipulates in its code of conduct that no weapons are allowed in its shopping centers, noting that exemptions to their code of conduct "will be determined by local center management."

Indiana has restrictions on who can possess a handgun, with it being illegal for people who have committed felonies and those under the age of 18 to own or carry one.

The recent spike in tragic shootings has pushed guns to the forefront of a national debate as US leaders grapple with how to reduce the alarming rate of violence.

Two shootings in May that left 21 people dead, mostly young children, at an elementary school in Texas and 10 Black grocery patrons dead in upstate New York revived the US' bitter debate over gun regulation.

The US Senate recently passed a bill aimed at curbing the gun violence ravaging the United States, which has been particularly rampant over the past couple of months.

Indiana’s new handgun law, which took effect July 1, lifted the permit requirement to carry, conceal or transport a handgun in the state.

Biden called on members of Congress to pass tougher laws just a day after a mass shooting in Tulsa, Oklahoma, over a week after a school massacre in Uvalde, Texas, and almost three weeks after a mass shooting in Buffalo, New York City.

The Democrat called on lawmakers to raise - at a minimum - the age at which assault weapons can be purchased from 18 to 21. He highlighted the "unconscionable" fact that the majority of Senate Republicans do not want any of these proposals to be debated or come up for a vote.

Other measures include bolstered background checks, a ban on high-capacity magazines, maintaining safe storage of firearms, and allowing for the liability of gun manufacturers for crimes committed using their products.