MEXICO CITY – Enrique Pena Nieto took the oath of office as Mexico’s new president Saturday, vowing to restore peace and security and take on the vested interests that have hindered economic prosperity.

As several hundred protesters threw fire bombs at police and smashed plate glass windows, Pena Nieto marked the return of the Institutional Revolutionary Party, or PRI, with a 13-point plan heavy on old-party populist handouts but with reforms designed to boost the economy and modernize the education and justice systems.

“Mexico has not achieved the advances that the population demands or deserves,” Pena Nieto said in an inaugural speech unusual for its heavy emphasis on policy. “It’s time for us together to break the myths and paradigms and all else that has limited our development.”