CHICAGO (AFP) - A mask-wearing gunman opened fire at a shopping mall in Indiana on Wednesday (Oct 29), injuring three people, the local media reported.

An employee at a Target store told Indianapolis broadcaster RTV6 that she heard 15 gunshots.

Other witnesses said the shooter was escaping on foot wearing a ski mask and dark clothing.

Police told local media previous reports by witnesses that the shooter had "an AK-47 or a shotgun" were incorrect, but that he was still at large.

In a briefing to local media, police said the shooter and the worst-off victim, who was in critical condition but expected to survive, knew each other.

They reported that after the shooter entered the mall he found the victim and an argument ensued, after which shots were fired. Other victims were likely hit by ricochets.

In total, two men and one women had been shot and were suffering non-life-threatening injuries, broadcaster WTHR said.

The suspect was still at large.

In the wake of several high-profile mass shooting in recent months, combatting gun violence has emerged as a major topic of the US presidential election campaign.