Shoppers took for cover inside mall bathrooms after hearing gunshots inside a St Louis mall.
Photos online show a crowd of people hiding near the stalls while police send multiple units down to the scene.
Reporters at the scene of West County Mall say there are multiple units with blue flashing lights outside, with one video revealing a large number of officers scrambled to the incident.
One shopper who took cover in the bathroom wrote on Twitter: “Currently hiding in a bathroom at the mall on a Friday night in St. Louis because shots were fired in the mall. GUN CONTROL NOW.”
One witness claims to have seen the gunman, who shot from the second story and came down the escalator and kept shooting.
The man said he heard at least six gunshots and ran into the GAP store to call 911 and hide.
According to KSDK News reporter Casey Nolen, Mo Highway Patrol says the shooting started as an argument between two people, and one person is in custody.
St Louis County Police Department has confirmed they are assisting with a report of a shooting but have not released details on whether anyone has been injured in the event.
Kim St Onge, from KMOV reported: “Massive police presence at the West County Mall. People inside say they heard at least one gunshot and went running.
“I just talked to a group hiding in the bathroom at California Pizza Kitchen.
“They just got the go-ahead to leave from the manager they said.”
However, some others hiding in the bathroom have not yet been told it’s safe to leave yet by police, they say.
It’s also believed multiple police departments were sent to the scene, with Des Peres Police assisting.
The call came in shortly before 9pm local time (3am GMT).
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The second floor of the mall has been cordoned off by officers and those who took cover are believed to be leaving.
There are unconfirmed reports one person has been shot, with police yet to confirm.
It’s understood some witnesses did not see a gunman but heard at least one shot and then screaming.
Des Peres DPS has said police are doing a sweep of the mall but told local news there does not appear to be any “immediate danger”.