FOR RELEASE AT 7:00 A.M.
                                                          NEW YORK CITY TIME, ON
                                                               NOVEMBER 20, 2001



              INTERNATIONAL BANCSHARES CORPORATION COMPLETES TENDER
                  FOR NATIONAL BANCSHARES CORPORATION OF TEXAS

         LAREDO, TEXAS, November 20, 2001 - International Bancshares Corporation
(NASDAQ: IBOC) announced today that its subsidiary NBC Acquisition Corp. had
completed its tender offer for all outstanding shares of common stock of
National Bancshares Corporation of Texas at a price of $24.75 per share.

         International Bancshares stated that, based upon a preliminary count, a
total of approximately 2,920,226 shares of National Bancshares common stock
(including guaranteed deliveries) representing approximately 70.78% of the
shares outstanding on a fully diluted basis, had been validly tendered and not
withdrawn pursuant to the tender offer which expired at 5:00 p.m., New York City
time, on Monday, November 19, 2001, and that all such validly tendered and not
withdrawn shares had been accepted for purchase and payment in accordance with
the terms and conditions of the tender offer. Payment for the shares accepted
will be made promptly.

         As previously announced, any shares of National Bancshares common stock
not tendered and purchased pursuant to the tender offer will be acquired in a
subsequent merger transaction at the same $24.75 per share in cash.
International Bancshares intends to complete the merger transaction as soon as
practicable. Upon completion of the merger, National Bancshares would become a
wholly-owned subsidiary of International Bancshares.

         THIS ANNOUNCEMENT IS NEITHER AN OFFER TO PURCHASE NOR A SOLICITATION OF
AN OFFER TO SELL SHARES OF NATIONAL BANCSHARES. THE TENDER OFFER HAS BEEN MADE
PURSUANT TO A TENDER OFFER STATEMENT AND RELATED MATERIALS (INCLUDING AN OFFER
TO PURCHASE, LETTER OF TRANSMITTAL, AND RELATED TENDER OFFER DOCUMENTS)
REGARDING THE ACQUISITION OF NATIONAL BANCSHARES, WHICH HAS BEEN FILED BY
INTERNATIONAL BANCSHARES AND NBC ACQUISITION CORP. WITH THE SEC. YOU ARE URGED
TO READ BOTH THE TENDER OFFER STATEMENT AND THE RELATED SOLICITATION/
RECOMMENDATION STATEMENT REGARDING THE TENDER OFFER FILED BY NATIONAL BANCSHARES
WITH THE SEC BEFORE MAKING ANY DECISION REGARDING THE TENDER OFFER AND RELATED
TRANSACTIONS. THE TENDER OFFER STATEMENT, THE SOLICITATION/RECOMMENDATION
STATEMENT ON SCHEDULE 14D-9 AND OTHER DOCUMENTS FILED WITH THE SEC IN CONNECTION
WITH THE TENDER OFFER ARE AVAILABLE FREE OF CHARGE FROM THE INFORMATION AGENT
FOR THE TENDER OFFER, INNISFREE M&A INCORPORATED, 501 MADISON AVENUE, NEW YORK,
NEW YORK 10022, OR CALL TOLL-FREE AT (888) 750-5834.




                                  * * * * * * *

For more information, contact:

Dennis E. Nixon
Chairman and CEO
International Bancshares Corporation
(956) 722-7611


Marvin E. Melson
President and CEO
National Bancshares Corporation of Texas
(210) 403-4211

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