UPDATE 2-U.S. regulators close three small Illinois banks

(Adds failure of Rock River Bank of Oregon, Illinois)

WASHINGTON, July 2 (Reuters) - U.S. bank regulators on Thursday said they closed three small Illinois banks, bringing the total of U.S. bank failures so far this year to 48.

The Federal Deposit Insurance Corp said regulators closed Rock River Bank in Oregon, Illinois, John Warner Bank of Clinton and First State Bank of Winchester.

Rock River Bank had total assets of $77 million and total deposits of approximately $75.8 million, the FDIC said.

John Warner Bank had total assets of $70 million and total deposits of about $64 million, the FDIC said. First State Bank of Winchester had total assets of $36 million and total deposits of about $34 million.

The resolution of the failed institutions is expected to cost the FDIC's deposit insurance fund about $44 million.

The FDIC has faced a sharp uptick in failed banks as loan portfolios continue to deteriorate following the bursting of the housing bubble. In 2008 there were 25 bank failures, and just three in 2007.

The Harvard State Bank of Harvard, Illinois, will assume all the deposits of Rock River Bank. The State Bank of Lincoln will acquire all the deposits of John Warner Bank, while the First National Bank of Beardstown will acquire the deposits of First State Bank of Winchester. (Reporting by Karey Wutkowski; Editing by Richard Chang and Tim Dobbyn)