UPDATE 1-U.S. regulators close Citizens National Bank

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WASHINGTON, May 22 (Reuters) - Bank regulators closed Citizens National Bank, of Macomb, Illinois, on Friday, the 36th U.S. bank to fail this year as the struggling economy and falling home prices take their toll on financial institutions.

The Federal Deposit Insurance Corp said Citizens National Bank had $437 million assets and about $400 million in deposits. The failure is expected to cost the FDIC deposit insurance fund an estimated $106 million.

Morton Community Bank, of Morton, Illinois, agreed to assume the deposits of Citizens National Bank, who offices will reopen on Saturday as branches of Morton Community Bank.

Customers can access their money over the weekend by check, teller machine or debit card, the FDIC said.

In 2008, 25 U.S. banks were seized by officials, up from only three in 2007.

During the current financial crisis, Seattle-based lender Washington Mutual became the biggest bank to fail in U.S. history. It was closed in September while suffering from losses from soured mortgages and liquidity problems.

The FDIC will insure up to $250,000 per account.

The agency also has running a tally of problem banks that its examiners closely monitor. At the end of the fourth quarter, 252 undisclosed institutions were on that list.

(Reporting by Charles Abbott; Editing by Richard Chang)