The Wall Street Journal is reporting that mortgage lenders are facing an assault on yet another front as the mortgage debacle rolls on.

Investors, including Freddie Mac and Fannie Mae, are taking a long look at loans they have purchased from lenders over the last few years and the contracts that govern those purchases and are trying to force banks and mortgage companies to buy back growing numbers of troubled loans.

Many loan sales are governed by provisions that require lenders to take back loans that default unusually fast or contained mistakes or fraud.

Countrywide Mortgage, particularly hard-hit already, reported in a securities filing in May that its estimated liability for claims from investors was $935 million as of the end of March compared to $365 million a year earlier. The company has taken a first quarter charge of $133 million for claims it has already paid.

The Journal reports that many of the recent loan disputes revolve around claims of bogus appraisals, inflated borrower incomes and other misrepresentations made at the time the loans were originated. �Some of the disputes are spilling into the courtroom, and the potential liability is likely to hang over lenders for years.�

Fannie Mae told analysts in a recent conference call that it is reviewing every loan that defaults and seeking to force lenders to buy back those that did not meet promised quality standards.

Bond insurers such as Ambac Financial Group and MBIA are adding to the pressure. The latter company has been working with forensic experts to examine pools of loans that were supposedly composed of home equity loans and credit lines made to borrowers with good credit. The Journal quoted a MBIA official who said, that �there are a significant number of loans that should not have been in these pools to begin with.�

Lenders may feel it imperative to boost loss reserves in advance of any claims because of the potential for lawsuits. Three suits have already been filed against lenders by investors alleging the lenders understated their repurchase reserves.