Political pressure on some of the nation's biggest financial institutions grew Tuesday as a California lawmaker and the state's congressional delegation called on regulators to investigate the foreclosure practices of big banks.

The actions follow several recent announcements by three major lenders that they are halting evictions and some foreclosure proceedings, citing concerns over possible mistakes in their handling of the paperwork. These freezes are taking place in 23 states where courts have jurisdiction over the foreclosure process; they do not apply in California and other states where foreclosures usually take place without a court order.

However, California lawmakers said the admissions by Bank of America Corp., JPMorgan Chase & Co. and Ally Financial Inc. of possible errors in their handling of foreclosure documents may indicate a more widespread problem that could affect homeowners in the Golden State.

State Assemblyman Ted Lieu, a Torrance Democrat and author of several mortgage-related bills, called on two state agencies — the Department of Financial Institutions and the Department of Corporations — to impose a 60-day moratorium on foreclosures. Lieu wants the regulators to investigate whether big banks are complying with California law regulating foreclosures.

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"There is every reason to believe there is a worse problem here, because there is no judicial oversight," Lieu said. "There is no judge looking over the lender's shoulder."

Lieu said lenders might be violating a California law that requires them to contact borrowers and inform them of ways to avoid foreclosure. Another law requires financial institutions to have a loan modification program available to borrowers.

Also Tuesday, California's Democratic congressional delegation wrote a letter to federal regulators, including U.S. Atty. Gen. Eric Holder and Federal Reserve Chairman Ben S. Bernanke, asking them to investigate delays and possible irregularities in loan modification and foreclosure processes.

The letter, signed by House Speaker Nancy Pelosi (D-San Francisco), Rep. Henry A. Waxman (D-Beverly Hills) and other lawmakers, asks the agencies to "investigate possible violations of law."