America's biggest public pension system filed a formal objection on Wednesday to a quest by San Bernardino to seek bankruptcy protection, citing the "disarray" in the Californian city's finances.

San Bernardino, a city of 210,000 people 60 miles east of Los Angeles, declared bankruptcy on August 1. Since then it has halted pension payments to the powerful California Public Employee Retirement System (Calpers), its biggest creditor.