Police say the lockdown at Nanaimo's Woodgrove Centre Monday night was triggered by a boy wielding a replica handgun inside the mall.

Heavily armed Nanaimo RCMP officers responded to the mall with rifles drawn Monday evening after reports of a person with a gun inside.

The RCMP said Tuesday that mall security reported a young male "had pulled out a handgun from his waistband" inside the busy shopping centre.

Security reported the youth was last seen entering the Avalon Theatre area.

Police dog units and the emergency response team were deployed, as well as frontline officers wearing hard body armour who evacuated the mall.

At around 6:30 pm, the boy was found near the mall and police recovered an imitation firearm, the RCMP said.

The mall was reopened around 7 p.m. and transit buses resumed their routes in the area.

"This was a dynamic scene that was handled in a calm manner by everyone involved," police said Tuesday.

The boy was held in custody to appear in court Tuesday morning. The allegations against him include possession of an imitation weapon, police said.