BLOOMINGTON, Minn. (AP) — Demonstrators chanting, "Black lives matter," converged in the Mall of America rotunda Saturday as part of a protest of police brutality that caused at least part of the mall to shut down on a busy day for holiday shoppers.

The group Black Lives Matter Minneapolis had more than 3,000 people confirm on Facebook that they would attend. Official attendance figures weren't immediately available, but pictures posted to social media by local news organizations showed the rotunda was full.

The Mall of America increased security, and police in riot gear were present. WCCO-AM reported that stores were closed for a short time, and signs were posted at some entrances advising shoppers that the east side of the mall was on lockdown.

After a final warning to disperse about 30 minutes after the protest began, police in riot gear began clearing the rotunda, the Star Tribune reported. A large group of protesters began leaving the mall, but others migrated to a shopping area and occupied two levels.

About an hour later, organizers sent out a group text message advising those who were still inside to exit.