Police officers blocked protesters from entering the Mall of America Wednesday during a planned demonstration by the activist group Black Lives Matter at the shopping hub.

Officers and security guards formed a line outside the mall, extending into a nearby parking garage. A crowd was heard chanting, "We shut it down." The number of protesters who'd arrived was unclear.

More than a dozen stores at the nation's largest mall closed beforehand. Some are near the mall's rotunda, a central gathering point at the massive retail center in suburban Minneapolis.

A message projected on an indoor monitor read, "This demonstration is not authorized and is in clear violation of Mall of America policies."

The protest two days before Christmas was aimed at drawing attention to the police shooting last month of a black Minneapolis man, Jamar Clark. The 24-year-old died the day after he was shot by police responding to an assault complaint.

A similar demonstration last December drew hundreds of demonstrators angry over the absence of charges following the police killings of unarmed black men in New York City and Ferguson, Missouri. Dozens of people were arrested.

The privately owned mall said another demonstration would mean lost sales. The massive retail center houses an amusement park and more than 500 shops spread across four floors, attracting shoppers from around the globe.

The mall sought a court order blocking the planned protest. A judge on Tuesday barred three organizers from attending the demonstration, but said she doesn't have the power to block unidentified protesters associated with Black Lives Matter -- or the movement as a whole -- from showing up.

"Our number one priority is the safety of everybody out at the Mall of America today," Bloomington Police Deputy Chief Denis Otterness said.

Gov. Mark Dayton said he sympathizes with protesters' concerns, but he stressed that the mall is private property.

Kandace Montgomery, one of three organizers barred by the judge's order, said the group wasn't deterred by the ban. She declined to say if she or her fellow organizers still planned to go to the mall, but she said she expected at least 700 people to show up -- including some who were prepared to be arrested.

On one of the busiest shopping days of the year, Montgomery said the retail mecca was the perfect venue for their demonstration to pressure authorities involved in the investigation of Clark's death to release video footage.

"When you disrupt their flow of capital ... they actually start paying attention," she said. "That's the only way that they'll hear us."

The Associated Press contributed to this report.