WASHINGTON — The Federal Reserve announced Friday it will auction an additional $100 billion in April to cash-strapped banks as it continues to combat the effects of a credit crisis.

The central bank said it would make $50 billion available at each of two auctions, on April 7 and April 21.

Through the end of March, the Fed has provided $260 billion in short-term loans to commercial banks through the innovative auction process. It also has employed Depression-era provisions to provide money to investment banks.

All the moves have been designed to cope with a serious financial crisis that has roiled U.S. and global markets and caused the near-collapse of Bear Stearns Cos., the nation's fifth largest investment bank.

The Fed has been holding auctions every two weeks since December to provide short-term loans to commercial banks. It started with auctions of $20 billion, then pushed the level to $30 billion, and in early March raised the auction amount to $50 billion as the credit shortage grew more severe.

In announcing the move to $50 billion last month, the Fed said it would continue the auctions for at least the next six months, unless credit conditions show they are no longer needed.

The auctions are just one of a series of unorthodox steps the Fed has taken to battle the current crisis. The biggest of those moves was an announcement that it was allowing investment banks to borrow directly from the Fed. Previously, only commercial banks, which face tighter regulations, had that privilege.

The Fed also said it would make available $30 billion in financing to support the sale of troubled Bear Stearns to JP Morgan Chase & Co., hoping to prevent a bankruptcy that could have rocked Wall Street.

Private economists said the auctions were having a positive impact but that troubles still exist in many sectors of the credit markets because of multibillion-dollar losses many financial institutions have suffered as the result of soaring defaults on mortgage loans.

"The Fed has worked some positive magic," said Mark Zandi, chief economist at Moody's Economy.com. "At least the panic has subsided as the risk of another major failure has receded given that financial institutions now have access to a lot of cash through the various lending facilities the Fed has established."

The Fed's auctions have drawn criticism from some that the central bank, and ultimately U.S. taxpayers, could be financing a bailout for big Wall Street firms that had engaged in risky lending practices.

Fed Chairman Ben Bernanke will face questions about the Fed's recent moves when he testifies on Wednesday before the congressional Joint Economic Committee.