BLOOMINGTON, Minn. — A mass of demonstrators chanting “Black lives matter” converged in the Mall of America rotunda on Saturday as part of a protest against police brutality that caused at least part of the mall to shut down on a busy day for holiday shopping.

The group Black Lives Matter Minneapolis had more than 3,000 people confirm on Facebook that they would attend. Official crowd estimates were not immediately available, but pictures posted to social media by local news organizations showed the rotunda was full. The organizer of the demonstration, Mica Grimm, estimated that about 3,000 people participated.

#BlackLivesMatterThe Mall of America increased security, and certain parts of the mall were closed for some time. Signs were posted at some entrances advising shoppers that the east side of the mall was on lockdown.

About 30 minutes after the protest began, a final warning to disperse was given, and police officers in riot gear began clearing the rotunda, The Minneapolis Star Tribune reported. A large group of protesters began leaving the mall, but others moved to a shopping area and occupied two levels. A small “die-in” was staged in front of several stores.