A mass of demonstrators chanting, "Black lives matter," converged in the Mall of America rotunda Saturday as part of a protest against police brutality that caused at least part of the mall to shut down.

The group Black Lives Matter Minneapolis had more than 3,000 people confirm on Facebook that they would attend. Official crowd estimates weren't immediately available, but pictures posted to social media by local news organizations showed the rotunda was full. Organizer Mica Grimm estimated that 3,000 people participated. The Mall of America increased security, and parts of the mall were closed for some time. About 30 minutes after the protest began, a final warning to disperse was given, and police in riot gear began clearing the rotunda, the Star Tribune reported. A smaller group then staged a "die-in" for about an hour. Police said 25 people were arrested, mainly for trespassing. - AP