RIVERSIDE, Calif. (AP) _ California's biggest public pension system has appealed a judge's ruling that allowed the city of San Bernardino to file for bankruptcy.

The Sacramento Bee says the move Thursday renews the bankruptcy battle between the cash-strapped city and the powerful California Public Employees' Retirement System.

CalPERS tried to have San Bernardino's bankruptcy filing tossed out of court earlier this year. The city owes the pension fund $17 million in overdue payments.

Last week the San Bernardino City Council adopted a tentative plan to deal with all its creditors, including CalPERS. But the plan remains secret while the city negotiates with those creditors via mediation.

San Bernardino, located 60 miles east of Los Angeles, filed for bankruptcy protection last year after learning it faced a $46 million deficit.