March 27, 1998

Press Release

MIDDLEFIELD BANCORP ANNOUNCES NEW INVESTMENT

Middlefield Bancorp Limited has purchased a US$4.5 million convertible note issued by Centurion Energy International Inc. pursuant to a private placement. The convertible note is a 2 year instrument with an 8% coupon convertible into Centurion Energy common shares at exercise prices of US$0.47 in the first year and US$0.52 in the second year. If the convertible note is converted during the first year, Middlefield Bancorp would hold approximately 9.6 million common shares of Centurion Energy or approximately 15% of the total fully diluted common shares outstanding. Centurion Energy is a Calgary-based oil and gas company with production, development and exploration assets in Tunisia and a 40% interest in an exploration license in Egypt. Centurion Energy's common shares are listed on the Toronto Stock Exchange.

The investment in Centurion Energy has been made for investment purposes only and Middlefield Bancorp does not currently intend to increase its investment in Centurion Energy. No other party is acting jointly or in concert with Middlefield Bancorp in regards to this transaction.

Middlefield Bancorp Limited is a Canadian corporation engaged in merchant banking activities. Managed by the Middlefield Group, the Company is dedicated to building long term value for its shareholders by seeking out undervalued situations. Middlefield Bancorp's common shares are listed on the Toronto Stock Exchange under the symbol "MBN".

For further information, contact in Toronto, Canada:

Dean Orrico
Vice President
(416) 362-0714