CHICAGO -- Several police cars were damaged, including at least one set on fire, as protests continued Saturday over the death of George Floyd, a handcuffed black man who died after a Minneapolis police officer pressed his knee into his neck for several minutes.

Officers struck multiple demonstrators with batons amid the protest near the Trump Tower on the city's Near North Side, the Chicago Sun-Times reported. Video sent out by another local reporter also showed police in tactical gear walking on a downtown street.

Chicago Mayor Lori Lightfoot announced a 9 p.m curfew that runs until 6 a.m. Sunday.

Lightfoot condemned Floyd's death during a Saturday night news conference and defended the idea of demonstrating to honour him. But she added that a peaceful protest has "devolved into criminal conduct" and police will be aggressive with arrests for anyone caught damaging property.

"When you or anyone else behaves in this way, we all lose by giving the very same forces of oppression we are fighting against the false validation that they crave," the mayor said.

The crowd of thousands converged on Chicago's Loop for Saturday's protest march. The demonstration began at 2 p.m. and protesters began marching north about 90 minutes later, the Chicago Tribune reported.

Saturday's demonstration came after Chicago officials, following overnight clashes with protesters, asked that additional protests remain peaceful. Demonstrations are expected throughout the weekend over Floyd's death.

Chicago police Superintendent David Brown said peaceful protests that began Friday afternoon turned more confrontational as the night wore on, resulting in 108 arrests. Protesters blocked traffic along major streets, threw bottles and other objects at police vehicles and shattered the windows of downtown businesses.

About a dozen squad cars were damaged and some officers suffered minor injuries, including a broken wrist.

The violence in Chicago and many other cities was sparked by anger over over Floyd's death in Minneapolis on Monday, which was captured on cellphone video. It led to the firing Tuesday of the four police officers who were arresting Floyd for suspicion of passing a counterfeit bill and to third-degree murder and manslaughter charges being filed Friday against the officer who used his knee to pin Floyd down for more than eight minutes, even as Floyd pleaded for air and went limp.