Mayor Michael Nutter issued the new curfew rules after a series of violent attacks perpetrated by groups of youth.
"Nutter said additional police presence and a stricter curfew would be implemented in Center City and University City until the beginning of the school year.
The increased police patrols will cost the city $56,000 a weekend, Nutter said, adding that the public can call 3-1-1 to find out how to participate in the Safe Corridors campaign to help patrol targeted areas with community leaders.
Curfews for targeted areas will be 9 p.m. on Fridays and Saturdays for anyone under 18. Anyone caught violating curfew will be taken home or to a police station, Nutter said. For the first offense, minors face a $100 to $300 fine.
As for the rest of the city, the curfew will remain the same - 10 p.m. for children under 13, and midnight for young people under 18."