In court documents filed Tuesday, some of Detroit's creditors asked a bankruptcy judge to appoint a committee to value the collection of the Detroit Institute of Arts.

Since August, Christie's has been appraising a fraction of the museum's 60,000-piece collection. The appraisal should be done in December.

The group of creditors, which includes European banks, bond insurers, the city's retirees and labor unions, wants a valuation by a separate group in order to get the most out of any potential sale of the museum's artwork, according to the filing.

Straddled with 18 billion dollars in long-term debts, the city has defaulted on multiple bond payments. A ruling will be made next week on whether Detroit is entitled to municipal bankruptcy protection. If it is eligible for Chapter 9 protection, the city should file a debt restructuring plan by mid-December.

The museum's art is expected to be valued at more than $1 billion, the court filing stated on Tuesday. Creditors view a sale of artwork as a legitimate way of being paid by the city.

Museum officials have said that any sale of artwork from its collections would be "catastrophic" for the institution. The art is held in "public trust" and can't be sold, contends the museum.

Christie's is expected to provide alternatives other than selling the art, from renting out pieces to taking out loans on certain works.