Philadelphia police were being kept busy Friday night arresting dozens of teens caught breaking the city's new 9:00pm curfew.

Philadelphia Mayor Michael Nutter enacted the new curfew after three incidents of random attacks by groups of teens in Old City, Center City, and Fairmount Park.

According to The Philadelphia Inquirer, 15 teens who had been arrested after breaking the curfew were being held at Center City's 6th District by about 10:30pm local time.

Another 15 were being transported to the same station and 20 were being taken to the 3rd District.

In West Philadelphia's 18th District, police said there had been no arrests.

"Minors who are caught breaking curfew will be sent home, brought home or transported to a police station where their parents will be contacted," the city said in a press release. "Minors may be issued a citation with a $100 to $300 fine for a first offense."

The curfew applies to Center City and University City.

Nutter says parents of teens who participate in the attacks will face legal sanctions. The mayor adds that programs at youth centers and help for parents will be offered as curfew enforcement continues, MyFoxPhilly.com reports.

Despite the new efforts to contain the mob violence, only four of the 11 attacks since 2008 reportedly occurred after the new curfew hours, MyFoxPhilly.com reports.

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New Philly Teen Curfew Goes Into Effect: MyFoxPHILLY.com