Bank of America Corp unnecessarily burdened U.S. regulators who were reviewing the mortgage giant's foreclosure practices, according to a court filing.

Federal regulators and state attorneys general have been investigating bank mortgage practices that came to light last year, including the use of robo-signers to sign hundreds of unread foreclosure documents a day.

The Department of Housing and Urban Development inspector general's office conducted a review of the five largest mortgage servicers, including Bank of America, which is the biggest.

Departmental auditor William Nixon said BofA significantly hindered the review, according to a document filed in a lawsuit brought by the State of Arizona against the bank.

BofA was slow to provide documents and other information, Nixon said in a sworn declaration dated June 1.

When interviews were permitted, the presence or involvement of the bank's attorneys limited the effectiveness of those interviews, Nixon said in the filing.

BofA spokesman Dan Frahm said any suggestion that the bank had not fully cooperated was inaccurate.

We provided on-site and follow-up access to more than 55,000 pages of material and we voluntarily coordinated interviews and assisted with arranging depositions with two dozen employees, Frahm said in an email on Monday.

The inspector general's review found that banks did not have proper paperwork in place when filing to have the Federal Housing Administration reimburse them for federally insured loans on foreclosed properties that were sold for less than the remaining balance for the mortgages, according to a person familiar with settlement talks between the banks and regulators.

The state of Arizona filed its own lawsuit against Bank of America last year, accusing it of routinely misleading consumers about home loan modifications.

The case in the Superior Court of the State of Arizona, County of Maricopa is State of Arizona v. Countrywide Financial Corporation et al, CV2010-033580.

(Reporting by Dan Levine; Editing by Lisa Shumaker)