U.S. federal regulators have raised the number of struggling banks which they have essentially put on probation, forcing them to fix their problems to avoid potential failures, the Wall Street Journal said.

Citing data obtained under the Freedom of Information Act requests, the paper said The Office of the Comptroller of the Currency (OCC), along with the Federal Reserve, have issued more memorandums of understanding so far this year than in all of 2008.

At the current rate of at least 285, the Fed, OCC and Federal Deposit Insurance Corp are in line to issue nearly 600 of these secret agreements this year, the paper said, compared with last year when 399 such agreements were issued.

The memorandums -- which can force financial institutions to increase their capital, overhaul management or take other major steps -- are not bound to be made public by the banks, the Journal said.

The OCC, a division of the Treasury Department that supervises national banks, could not be reached outside regular business hours.

(Reporting by Nivedita Bhattacharjee in Bangalore; Editing by Greg Mahlich)