UPDATE 1-U.S. closes banks in Florida and Arizona

(Adds closing of Legacy Bank in Arizona)

WASHINGTON Jan 7 (Reuters) - U.S. authorities closed First Commercial Bank of Florida and Legacy Bank in Arizona on Friday, the first bank closings of 2011 as smaller financial institutions, in particular, continue to struggle with the depressed housing market and tepid economy.

Last year, 157 banks failed, exceeding the 140 failures in 2009.

The bulk of the failures have increasingly been smaller institutions, each with less than a billion dollars in assets, as large banks have recovered more quickly from the 2007-2009 financial crisis.

The Federal Deposit Insurance Corp announced the following closure on Friday:

* First Commercial Bank of Florida. Had assets of $598.5 million and $529.6 million in total deposits. First Southern Bank of Boca Raton, Florida is to assume the deposits.

* Legacy Bank of Scottsdale, Arizona. Had assets of $150.6 million and $125.9 million in total deposits. Enterprise Bank & Trust of St. Louis, Missouri is to assume the deposits. (Reporting by Tom Doggett; editing by Tim Dobbyn and Andre Grenon)