LOS ANGELES - The U.S. Trustee has launched an inquiry into Countrywide Financial Corp.'s claims against two Florida borrowers seeking bankruptcy protection to determine whether actions of the nation's largest mortgage lender "threatened an abuse of the bankruptcy system."

The federal agency, which is part of the Department of Justice and oversees bankruptcy cases, filed subpoenas with the Bankruptcy Court last month demanding that the company turn over internal documents and provide sworn testimony in the cases.

The U.S. Trustee wants to examine what steps Countrywide took to determine its claims against the debtors, Manuel Del Castillo and Maria E. Pena, and William and Joyce Chadwick, according to court documents.

Countrywide, of Calabasas, Calif., filed objections to both subpoenas earlier this month, arguing that the U.S. Trustee was exceeding its authority and engaging in "an impermissible fishing expedition."

Last week, a Miami judge overseeing the Del Castillo and Pena case ruled in favor of the U.S. Trustee, and an order was being prepared for the agency to proceed with its request for documents.

A spokeswoman for the U.S. Trustee in Washington declined to comment yesterday.

Countrywide declined to comment on the nature of its claim against the borrowers or the U.S. Trustee's subpoena, citing a policy against commenting on pending litigation.

Donald F. Walton, acting U.S. trustee for Region 21, had opened an inquiry "to determine whether Countrywide's conduct in this particular case deviated from the standards established by the bankruptcy code and/or whether its particular actions threatened an abuse of the bankruptcy system and its procedures," according to court filings.

The agency wants Countrywide to show its legal basis for claiming the escrow advance, late fees, and why it increased Del Castillo's and Pena's monthly mortgage payment from about $1,783 to $4,773.

In the Chadwicks' case, Countrywide claims it is owed about $100,733 and more than $2,000 in late payments. The Chadwicks, who filed for protection under Chapter 13 of the bankruptcy code in West Palm Beach, Fla., have also objected to Countrywide's claim.

The housing slump and mortgage-market meltdown have led to soaring home-loan defaults and foreclosures, forcing cash-strapped borrowers to file for bankruptcy protection and leaving mortgage lenders scrambling to recover whatever they can to minimize their losses.

Shares of Countrywide fell 25 cents, or 2.79 percent, to $8.72 yesterday.