An internal audit says Philadelphia has the worst accounting practices of the nation's 10 largest cities.

The audit, released Tuesday by City Controller Rebecca Rhynhart, cites $924 million in bookkeeping errors last year alone.

The city is also missing $33 million from its main bank account, a discrepancy that came to light earlier this year.

Philly.com reports that city finance officials plan to have answers on the missing money by November. Rhynhart says there's no indication of whether it was an innocent mistake or an act of fraud.

The audit report says the city's accounting system is ripe for fraud, with too few accountants and inadequate technology.

Rhynhart says the finance department improperly relies on auditors from the controller's office to reconcile the city's books.