Public protests and demonstrations in Philadelphia in response to the death of George Floyd and against alleged police brutality began as peaceful assemblies but have since turned more violent as the evening continued.

As one major protest intensified, Democratic Mayor James Kenney announced a "mandatory curfew" set to begin at 8 p.m. ET through early Sunday morning.

A reportedly peaceful Center City demonstration of about 500 calling for "Justice for George Floyd" assembled in the afternoon and moved northwest toward the Philadelphia Museum of Art, according to local FOX affiliate WTXF.

However, a separate protest later materialized in Penn Square, home to City Hall, and turned increasingly violent.

The iconic statue of famed former Philadelphia Mayor Frank Rizzo was defaced and CBS3 video from the scene showed protesters concentrating in the public courtyard in the center of City Hall, where some demonstrators climbed atop glass fixtures near the SEPTA subway entrance.

Rizzo, who came from a storied Philadelphia family, served as mayor in the 1970s during which he was praised for his devotion to public service. The outspoken Rizzo, however, also served as the city's police commissioner for several years and has been criticized for his fraught relationship with the African-American community during that time.

Not far from City Hall, at least a dozen storefronts along the popular Chestnut and Walnut Street corridors were either looted or defaced, and several Philadelphia Police Department vehicles were reportedly set ablaze in the vicinity -- as well as one Pennsylvania State Police cruiser, according to CBS3.

Manuel Smith, an editor for the CBS affiliate also tweeted video of a Starbucks engulfed in flames on Dilworth Plaza -- which sits along the west rampart of City Hall.

In remarks on Twitter Saturday evening, Mayor Kenney said he appreciated the message of the peaceful demonstrations that occurred earlier in the afternoon, but condemned the conflagration in Center City.

"The peaceful protests earlier were touching showings of our collective grief," Kenney wrote. "The anger being displayed now cannot continue. Please have respect and dignity for each other and return home."

Shortly after that post, Kenney retweeted the police department's message announcing the mayoral-imposed curfew.

The Police Department echoed Kenney's sentiment about the earlier protest at the Art Museum, but declared some of the protesters in Center City as committing "criminal acts."

"Those acts will not be tolerated, and we strongly encourage everyone to refrain from entering Center City. We will continue [to] provide updates throughout the evening," the Department said in a statement on social media.

As the evening continued, police officers in riot gear reportedly confronted a crowd near the Municipal Services Building at 16th and Arch Streets, according to FOX-29. Officers were said to have pressed the crowd back as they threw projectiles and trying to push through the line of police by using a fence.

The affiliate also reported through a source that one armed man was arrested in area and charged with firearms violations.

In the surrounding suburbs, smaller protests cropped up, including one several miles to the south in Delaware.

A group of peaceful demonstrators outside Wilmington, the state's largest city, were able to temporarily block off a stretch of Interstate 95. FOX-29 photos showed protesters holding signs and blocking vehicular egress.

North of Philadelphia, another peaceful protest materialized at the Rose Garden in Bethlehem, Pa., which is also about 70 miles west of New York City.

Demonstrators objecting to police brutality marched east along Broad Street toward Payrow Plaza in the center of the Christmas City -- which contains City Hall, the police department and city library -- according to Lehigh Valley Live.

Chants of "no justice, no peace," were heard as the group moved toward downtown Bethlehem.

The demonstrators remained peaceful, the outlet reported, though an intersection on New Street was temporarily blocked by demonstrators.

An organizer of the Bethlehem Protest, Matty Fall, told LehighValleyLive that the group did not agree with the violence being seen in other cities.

"We don't condone it at all," Fall said. "We're really just trying to get the message across that this can't keep happening."